Well, I am not sure if I qualify as a pro, but here's what I use. For tech planets, it's basically the largest planet with the most research bonuses. That's a fairly simple one. Also, I try and build at least one research centre on every planet. Also, for about PQ 7 planets and below, if they don't have enough upgradeable tiles to get above 10, I almost always make them research planets.

For income, I generally go by the number of morale bonuses. Farming bonuses don't do you much good if you can't keep the crowds happy. You would want at least a PQ 11 planet, since that provides an extra morale bonus for planet quality. The rule of thumb is generally held to be one entertainment building per farm. You need more per farm once a planet's population goes above 20 billion. For stock markets, on an economic planet I just build one anywhere I haven't built anything else. Personally, I try to never allow a population higher than 20 billion except on one planet, so I can build a Political Capital and a Secret Police Centre in one place and hopefully keep it under control, plus use the space on other planets for other things. That said, if you can keep several planets with populations above 20b, don't change that part of your strategy.

And what are those little PQ6's best used for?

2 NLC and 3 SM.

For example, what planet quality / modifiers do you look for before saying "ah, that's an Econ planet", or "that's a tech planet".

Any planet is good for econ. For research I try to use a 26-32 with all NLCs. Then build econ SBs around it. Current game I am using a Class 22. Research production is 16461. the blue shiels run into the planet surface area.

Lastly, when I build an economy planet, what is the ideal ratio of farm : stock market : entertainment? Is there a rule of thumb for planet quality vs. number of farms?

Under PQ 7, no farms.
PQ 8-12, 1 SP, 2 Farms, 3 VRC, 2 NLC, X SM.
PQ 13-19, 1 SP, 2 IS, 2 Farms, 3 VRC, 3 NLC, X SM.
PQ 20-??, 1 SP, 2 IS, 2 Farms, 3 VRC, 4 NLC, X SM.

If you have 2-3 Morale resources you can run taxes at 69% with out any problems.

When deciding how to specialize a particular planet, I like to think about its "effective PQ" for each possible specialization. The EPQ is the planet's actual PQ plus a number that depends on the bonuses that planet has. For example, a planet with PQ 11 and a 300% bonus for research would have an EPQ of 14 for research, and an EPQ of 10 for anything else because I'd still put a lab on the bonus tile. EPQ can also include bonuses from moons, rings, colonization events, distance to enemy territory, and distance to other planets (for econ starbases). This will help you decide what each planet is suited for.

So here's how I specialize my planets:

The planet with the highest EPQ for research is my technology capital. This planet gets about PQ/4 factories because it needs decent production to build the rest of its improvements. It gets a spaceport so that those factories are not half wasted. It gets the tech capital and the omega research center, and the rest of the planet is filled with labs. This is so that the most labs possible get the big bonuses from the tech capital and omega research center. Once you've built all your discovery spheres or neutral learning centers, then you can convert the factories and starport to labs if you wish.

Next, the planet with the highest EPQ for production is my manufacturing capital. It has the manufacturing capital, a starport, and the rest of the planet is factories. It's convenient to build achievements, trade goods, and superprojects here because of the high production, but I try to avoid it because I don't want to replace the factories that get big bonuses.

Once those two special planets are chosen, all the planets with above average EPQ for economy are made into economy planets. Build PQ/4 factories and a starport just like the tech capital, build one or two farms and at least as many morale buildings, and fill the rest of the planet with markets. I specialize the good planets for economy because tax income is produced by multiplying the square root of the planet's population with the econ bonus from markets. This means that you get the most money by having a high population and many markets on the same planet, and this is only possible on a planet with high EPQ. These planets are also good for making trade routes because of their high populations. My best economy planet gets the economic capital, the political capital, and I move my civilization capital here for even more multiplication. The economic capital is often the highest PQ in my entire empire.

The mediocre to bad planets in my civilization are production and research planets. They have a starport, about one third factories and two thirds labs. Farms and morale buildings would be useless here because population doesn't help factories or labs at all and there aren't any markets to make population worthwhile. I generally don't specialize these planets for production or research because high production on a planet causes high wastage when overproducing a ship. You waste less if your production is evenly spread across all your planets. And a research-specialized planet needs factories anyway to build and upgrade its labs. On the other hand, a planet with lots of factories is good at building superprojects quickly, so I do that sometimes. And those planets that are PQ 5 or less aren't really worth building factories and starports on, so I just cover them with labs.

And sometimes a colonization event pops up and redetermines fate.

I mean if you pick the evil choice on throwing those pukes out in the sea and get a +49% tech on this world its defititely getting some labs.

At the begining of the game, i will colonise planets but not build anything at all.

You may as well have the planet build economic buildings. They have no maintenance requirement, increase your economy and use otherwise wasted production capacity. I'll often queue up 4 econ buildings and don't come back to build anything else until the planet is profitable.

certainly tho i do build markets this way in useless planets one i have a nice green financial position.

PQ 8-12, 1 SP, 2 Farms, 3 VRC, 2 NLC, X SM. PQ 13-19, 1 SP, 2 IS, 2 Farms, 3 VRC, 3 NLC, X SM. PQ 20-??, 1 SP, 2 IS, 2 Farms, 3 VRC, 4 NLC, X SM.

Newbie here, what do those translate as?

VRC Virtual Reality Center, NLC Neutrality Learning Center, the other's have me just guessing wildly.

Thanks for clarifying that for me DG.

& FC you are most welcome.

fc = fer chrissakes?

When do influence buildings come in or do you reserve those for starbases?