Pick very fast tech.
Turn off super events.
9 minor races.
Abundant all, of course!
Pick the federalists for the economic bonuses.
Pick super-breeders. Flip from 100% to 50% approval as cash allows from day 1.
This is basically a custom Torian race, but you can get slightly better bonuses with a custom race. The Torians are the only race for which I consider this to be true.
Pick four or five opponents (seems to be optimal, keeps the AI weak enough and limits group research).
Set relations to friendly for all opponents.
(I don't Ctrl-N, well rarely)
Use the all factory strategy.
Get lucky and get two economic and one morale resource on the initial push.
Focus on morale and economic techs (and move up to manufacturing centers early).
Build the MCC for the economic bonus.
Build extra survey ships early.
Stop colonizing early and focus on building a completely unbalanced society with only manufacturing centers (don't do ICs, so you can use them sooner) and two farms on every planet...I had about forty to fifty planets and they were all (yes, every single last one) manufacturing planets. Build the Artificial Slave Center. Even with the three galactic resources, all the morale and economic techs (and wonders), the MCC, and fully populated planets, this heads you straight for the wall. This is, so far, the first and only came that came together well enough for me to literally make every planet a manufacturing center.
Use this massive manufacturing advantage (start adding them up - racial bonus, survey ships bonuses, all tech bonuses, slave center, and all manufacturing planets) to beat the AI early...Just before you start hitting the wall. With research focus on all these manufacturing planets, narrow research focus (no colonization techs, etc.) and trade with minors, you should be able to get a limited tech advantage. Switching to 100% military production with forty manufacturing center planets moved me from no military to ~7 times the next strongest AI in about two months. I could pop out a fully loaded large ship every four to six turns on all planets with attacks approaching ~100 while the best AI was building mediums in the thirties and the worst AI was small in single digits.
Every planet added to your empire with all these bonuses should be net positive on the cash flow, even when nearly empty and should help keep pushing the wall back out.
Get lucky and get the economic prosperity event early and preserve it.
I did also use a good selection of dirty tricks on the AI...Pretty much every good dirty trick that has been posted in the last year...One is NOT generally known, has never been posted in the GCII forums, is game unbalancing and fits within the rules of a fair game...I did a bug report on in it in early DA beta, but it's still there. That is as much as I will say about that particular dirty trick!
I did build massive numbers of BHEs (leaving eight in orbit so you receive the bonus for being in planetary orbit). On a cost per point basis, it's not the most effective ship, but system limitations start to become more important. I did NOT build a military star base array. This let me run the game out extra years.
After fully populating the galaxy, I ran at ~28% approval all turns, except election turns (being one of those dirty tricks). I left the Yor with one planet to prevent victory (and another of those dirty tricks). I also left all planets with some manufacturing capacity and a starport. At some point I only use research focus on planets that don't have any social builds....Later this transforms into using focus on the odd man out planets (military when majority social builds and then flips to social focus with 100% military builds as they develop). On the final score, something like 10K or 11K from tech is typical. Almost all my points are coming from the economy and the military with a reasonable amount from social.
Also spend down under the 20K treasury penalty every turn, especially with the economic bonus. Peak gross income ~1.4 Million BCs a turn...I was using all of that on ship maintenance somewhere around year six???
Also (since I know you have the same video card as I do) after a couple of years my video card will time out on game load, even with everything turned down or off. I've found that if I load one of the earlier saved games and then load the current saved game, it takes less time to load the current saved game and I can avoid the video card timeout...Most games.
I'm sure there is more...But that is what comes immediately to mind.