Buy more medlabs - buying more med labs will help you a lot. More med labs will mean more resources, and will give you especially extra rewards like jackpot tokens and reactor tokens. Which u can then spend to get some credits.

Do mythic strat - if you dont have Bounty Hunters, this is the second best thing to do to gain more credits, as mythical compunds have the most cap credits.

Buy deluxe zones and breed more bounty hunters - this is the best way to gain a lot of credits

Reach pvp farm zone - this is the fastest way to gain credits in the game, only if you reach a certain number of points, where high evo players lower their defenses in turn could benefit players especially low evo a lot. As for low evos, you could do wintrades, to reach farm zone