Don't waste time building a xeno farm first. Food is a hard limit on population, but doesn't directly impact growth. The growth buildings that do exist are so weak they're not worth buying.

Focus your planets. On your homeworld, just spam factories. On the next planet, you can spam research buildings. You're aiming for 1 econ planet, 2 industry planets and 7 research worlds for every 10 in your empire. Focus very big planets on research, medium planets on industry and small planets on wealth. Some would argue that it's better to build nothing at all for the first 100 turns or so; that's actually true, but not as much fun.

Every planet should have 2 approval, 2 farms and at least 1 factory. Build the factory first and the farms last, with approval buildings immediately before them. Coat the rest of the planet with the correct type of resource improvement, adding in hubs if there's 4 or more sectors adjacent to it. Every industrial planet should have a shipyard as the final item in the queue. Put every planet to 100% manufacturing until it's finished building everything.

Once you've built everything on a planet, check what type of world it is. If it's an industry world, set it to 90% military manufacturing and stick a pop growth project in the main queue. If it's a research or econ world, reset the main wheel to 95% for the appropriate resource, stick the correct project in the queue, and then ignore it for the rest of the game.

Spam nothing but colony ships, and put the minimum amount of population in each. Keep building them even when your homeworld can no longer put 0.5 pop in them. The fastest way to grow your pop is building more colonies.

That should get you ahead of the AI.

Yup. Buildings cost maintenance and require you spending production that could better be used on colony ships.

Always, always, always get at least a farm. Your first farm increases your base production by more than any bonus building. The approval building is probably not worth having, since on a large map Large Empire Penalty will render it useless fairly quickly.

It works if you're doing extreme colony rushing.  Each new colony adds production that you can balance so it costs nothing while adding research and manufacturing to your empire. Once you rush colonize, you can start building and specializing the colonies without putting stress on your budget.  I've never done this because it doesn't sound fun to me and doesn't work so well on higher difficulties.

I don't do extreme colonizing.  My games are more built up and based on a defensible position.

I prefer to build my homeworld with 3 factories and fill it up the rest of the way with labs, rush buying until I have at least 3 labs.  If I have a secondary planet, it becomes all factories.  I generally build 3 factories as my first buildings on all of my planets and fill them out with whatever they're being specialized for.  No hard and fast rule, though, since each game is unique and staying flexible is how I beat the higher difficulties.

I don't bother with farms until my planets start to bump up against the pop limits. 

Don't forget the production slider.  My global one starts at 50/50 manufacturing and research, 1% econ with 100% social. Yes, that's 101%.  Any planet that I want to add to a shipyard or specialize gets its own setting. Shipyard planets are generally 99% manufacturing, 1% econ and 1% research. 

Once you get the higher terraforming techs, you can go heavy factories and econ. Money is real nice because you can upgrade those ships that are floating around close to the enemy instead of having to wait until a fleet is built and moseys across the galaxy.  That becomes pretty important when you're racing towards a newly discovered planet or resource. If your survey ship finds a small fighter, it can quickly become a constructor and extend your range.

I found the hard way to pay attention to the economy.  You don't need bundles of cash, but you don't want to go negative. If you do, you can't produce anything until you're out of the red.  Two or three turns of that can set you back dozens of turns over the game span.

I don't build military until I need them.  Most of the time, that means medium capital ships as my first fighters, turning to carriers as soon as possible. If the AI's getting aggressive, it might mean small missile only ships to keep them calm.  I specialize my military in missile ships.  it's better to have one decent weapon rather than multiple weak ones. I could just as easily go beams, but the AI likes them and I can trade for the tech later.  I don't bother with defense. Missile ships can lob away at the enemy from long range.  

My armed survey ships go after ship graveyards and my unarmed ones go for artifacts, capsules and space junk for the most part. Those anomalies come in handy.  I eventually have a fast large survey carrier ship scooping up the remaining ship graveyards.  There are only two small pirates guarding those, so one carrier module and a missile on a large hull will do the trick.

Good hunting.

Those other silly features in the game like "farms" or "factories" are actually pointless and exist only to confuse the player.  YOU DON'T NEED THEM.  IF YOU BUILD ANY IN THE FIRST 50 TURNS YOU ARE PROBABLY PLAYING THE GAME WRONG ON LARGER MAP SIZES WITH LOTS OF PLANETS TO COLONIZE.

The most optimal path to winning the game on larger map sizes with lots of planets IS TO BUILD NOTHING EXCEPT COLONY SHIPS FOR THE FIRST 50 TURNS.  Use Colonizer to rush buy shipyards on your colonies, and USE THOSE SHIPYARDS TO BUILD NOTHING EXCEPT COLONY SHIPS.

Your military spending should be 100%/100%.  EVERYTHING should be devoted to building colony ships and using colonizer to rush buy shipyards in your new colonies.  

If you built anything else (with the possible exception of Hives or Gaia Vortex) YOU ARE PLAYING SUB OPTIMALLY.  

Well, yes.  But he's asking for the most optimal method TO WIN.  I am merely giving him what he wishes.  

"I don't bother with farms until my planets start to bump up against the pop limits."

How do you tell what your population limits are?

The whole colony module on a tiny hull at the start has been nerfed with 1.1. Transport Specialization only provides -20% instead of -30%. You can still get one on a small hull with dense but it's not really worth the effort. That whole tactic is a bit of a crutch anyways. You should still have no trouble out colonizing the AI even on very high difficulties using regular cargo hulled, intelligently designed colony ships (aka not the stock garbage) if you bother to set yourself up properly for the colonizing phase. Wasting your colonizer trait on a shipyard for every planet is also not the smartest. You're better off holding on to it since it doesn't have to be used immediately and just setting each world you colonize to pure research or economy unless you find a nice clump of worlds you can turn into a ship building powerhouse. Once the colonizing phase is over you can go back and build up however you like using the colonizer perk to get a jump start on getting your worlds going.

Your population limit is equal to the amount of food produced on the planet. You can look at the planet window to see the total food produced or alternatively you can mouse over the population icon in the sidebar for the planet in question  and the top right corner of the tooltip will say something like 4.5/10 where 4.5 is the current population and 10 is the maximum amount it can support without starvation.

Yeah, you don't have to only produce colonizers or pick exactly the right race traits by any means - as I say, it's intensely boring if you do. The AI in vanilla has no idea how to respond to it, and it's pretty blatantly unnecessary. 

All great info, thank you!

What's interesting to me is that I bumped up the number of pirates in the universe in the hopes of trying to slow the AI down so I could have a chance to catch up, but evidently the AI is MUCH better at handling the pirates than I am because by the time I got up enough tech and production to start attacking the pirate bases I ended up being way behind on my expansion building.

It almost seems like the AI is cheating because the AI would have to develop fighting ships early to take out the pirates which theoretically should force them to waste time building fighters and slow down their expansion, but in the end it seems like they can magically eliminate pirates (or avoid them completely) so I just shot myself in the foot.

Using a colony ship rush is kind of a craps shoot on a map filled with pirates because the colony ships can't get past (or to) certain areas of the map without being mobbed by pirate ships (slowing down or stopping the colony rush), but perhaps tweaking the build of the colony ships would make them able to outrun the pirates!

Of course I can just cheat by setting pirate bases to a very low number or none at all, but then wheres the fun in that?

I feel like I'm at something of a disadvantage here because a lot of people are coming from GC2 and are VERY familiar with how the tech trees work and what techs to get when to do what.  The mouse tool tips are definitely helpful and give some idea of what to do, but as far as coming up with strategies that combine different elements I think it's going to take a while for me to FULLY understand what's going on.  For example, what is the relationship between food, population and population growth.  In this case there is a tech specialization that says it gives +1 to food, but what does that actually MEAN?  Does +1 to food speed up growth or does it have to do with increasing the population cap?  Not knowing EXACTLY what something does means I'm probably wasting my time (and research points) if the trait is useless in my strategy.  Also, when a tech says it gives +10 to research in the tech tree, I am assuming this is a GLOBAL bonus, but when you build a building type on a planet that gives +2 to population, then the bonus is only to that one planet.  I think I have that one right.

Also, it sounds like there are some game design issues, for example if building certain planet improvements are "worthless" or "useless", they why are they in the game?  To distract and confuse people? 

Finally, how many enemies are people playing against?  I have been using 9 opponents and abundant minor races. 

Would I get entirely different results by dropping 100 opponents into the game?

Might try that tonight....

I like pirates.  I use them to protect my planets early on. If you build a sensor ship (a cargo ship with a bunch of sensors), you can see out a good distance.  Your colony ships should be a tad faster than pirates and you can go around them.  I like to use a fast scout or constructor to move the pirates to where I want them. Just move close enough that they notice you, but just outside their movement range.  They'll follow you around like puppy dogs.  Just jet out when you're close to where you want them and they'll stay there until something else catches their eye.

As far as food goes, 1 food = 1 pop, which evidently means 1 billion people.  You can get your pop growing faster with the growth techs and buildings.  A hospital is a growth building, but it also adds one pop to any adjacent farm. I like paring them up.

You'r right as far as a tech giving +1 or +10 to your empire and a building generally giving +1 or whatever to your planet. There are exceptions, but they're specified in the game. For instance, an Embassy gives +1 diplo skill to your empire, even though it's built on a planet. 

I'm playing with vanilla races against vanilla races on large or larger maps. That limits me to 7 opponents other than the minors.  I haven't thought about going to 8 opponents.   Guess I could play against a race identical to my own.  I haven't tried that.

Something to keep in mind is that the AI is aware of more than you are.  At normal and below, it's pretty even, but the Fog Of War is lifted for them on the higher difficulties.  That might explain why you see them as able to go around the pirate easily.  It also can explain why an AI is making a beeline from across the galaxy to that class 16 planet you have your eye on.

Funny thing though, you'll see the AI building ships that you designed later on.  It even names them similar to how you name your ships.  I've seen carriers with my initials on them and sensor ships floating around.

They only boost population cap.

boosts population cap.

It is equal to food produciton on that planet.

No, though you'll struggle to get it over about 300.

Raising pop growth is much better early on, but is also nearly impossible to do anything about (the buildings etc which do it are terribly weak).

Yes.

Excellent!

Thanks again. 

That's exactly what I needed to know. 

Ship design also appears to be central to a lot of people's strategies so I'll have to dig into that.  Right now I've just been using the stock ships, and that's probably part of my problem.

Quoting sjaminei,

reply 16

Seems to me someone should sneak onto marigoldran's comp and make a custom mod for him. Triple the cost of colony modules should do it? Or should we quadruple it?

I'll sell the Gal Civ III equivalent of junk bonds (ie. snuggler colonies and other useless resources) to the AI to finance my expansionist needs.