This will probably be considered an exploit and be fixed after posting this. It does make the game trivially easy once you do it. Planned on exposing a few of these, but with only being allowed 3 posts/replies as a new member ill just do this one.
Gather as many resources as possible (Durantium, Elerium etc), this worked really well for me since I usually set them to be common or abundant. Also, I set minor races to be common, which made this even easier since they hoard a lot of cash, and never seem to attack you when at war.
Start a trade with the cpu. Offer them every single resource you have in exchange for as much tech or cash as you can get. Declare war and you instantly get all that bac,k but keep what they gave you. Charge them to make peace later and repeat.
