I hear you.  236 turns into a game on immense, I have 300,000 credits and am making over 11,000 per turn.  I could put more into manufacturing/research and cut down on that income but I hate the coercion penalties.

I've got a raw production of 6523, savings per turn 10938, trade income 1876, tourism 734, for a total income of 13548. Expenses are 1147 for ship maintenance, 649 for colony maintenance, 253 for star base maintenance, for total expenses of 2051.  I have 55 colonies with a total population of 2,417.8.  I've also got 4 economic anomalies (for a total +100% at the moment). I have a banking sector on most planets, and my home world has the financial capital, citadel of revenue, and trade capital.  And then there are the various wealth boosting techs like wealthy population, federalist party, pacifist party, etc. 

So that's how I got to 11K per turn.  I think it's due more to lots of population than wealth buildings.

They could put a simulated stock market in the game then play the market.

Hm, ok, I have most of the economy boosting techs (although presumably not as much as Publius since I play with tech rate very slow). Also I don't have those economic relics because I play with relics on rare. But still that doesn't explain the difference. Surely I don't favor my economy that much, most of the time I'm content with running a moderate profit of 50-100 credits and rather concentrate on research and manufacturing, but still ...

Perhaps it's the population, my planets have about 20-40 pop each, but most of the time I have to load some of that in transports since I'm engaged in a long running war.

Update your ships That's the most expensive action in the game I think. Several thousand credits per single ship are not uncommon.

Ok, I don't pay enough attention to pop growth I have to admit. I appreciate the Food Distribution advice. I am also usually too lazy to destroy and rebuild improvements when more tiles become available ...

Having a large pool of money is very useful for upgrading your fleet, even a seemingly endless supply of cash can be put to good use this way.

So am I. I find having enough money is a big problem for me. Is there a special trick involved?

And don't forget to establish trade routes.

There is no special trick.  And I have no idea how different your gameplay is from mine or how it is different.  

I make a practice of using balanced management of small and medium planets, so they are making just enough to pay for themselves.  Then, the big Wealth planets are making actual profit for the empire.  I manage population so it is always growing, which affects Wealth, Research and Manufacturing all at once.  I create a limited number of small fleets with big ships to avoid tons of ship maintenance.  One thing that is possible is to emphasize ship manufacturing too much and outbuild your cash flow.  This is an argument against defending each planet separately in large empires.  I avoid as much coercion as I possibly can.  I consider all of these things as reasonable to do and the Wealth results are just one result from this core careful economy management. 

I am not looking for maximum Wealth.  I am looking for maximum Raw Production and efficiency.  Maximum Wealth is just one byproduct of that.  

I am convinced that this is only one possible approach and other principles are also valid.  Consider this as free advice with the usual money back guarantee.  

Intimidation Center.

I play on Immense or Insane.  It really isn't about fresh colonization.  I have sparse factions spread across the galaxy.  Empires are easily 30-50 planets each.

I have been persuaded to try smaller maps with more factions and much tighter spacing.  I would estimate starting empires as 8 to 12.  The same principles are applied to my economy as in larger empires. They just don't achieve the same levels of positive feedback loop acceleration as quickly.  However. if I start conquering, the feedback loop will start kicking in pretty quickly.  Then I am back to swimming in Wealth, Research, and everything else.  Please note that this is not a complaint.

In my late colonization phase, I have usually built a lot of improvements on my starting planets, improvements that start building up maintenance costs.  Even if the planet is overall profitable, it will be by just a credit or two.  If I don't start working up Wealth planets, that will start to mount up and the overall economy will bog down.  So the Markets start kicking in and I start making appreciable money.  This gets me investment in Asteroid Mines and cash for Diplomacy trades.  Also, I like rushing certain key buildings.  This all very good and keeps things accelerating throughout the game until  late stage.  Somewhere in there, the Wealth production balloons to larger numbers.

I could theoretically convert the Wealth planets to some other function, but, actually, I have the same issues with Research and Manufacturing.  All my problems in life should involve too much success.

Presently, I am trying a different custom faction that doesn't fit my play style so well. At the same time, I am moving down from Incredible and Godlike. I have different abilities, traits, and tech tree.  If sheer culture shock is a mark of successful variation, I am on the right track.    We will see how it works out.