Also if you can get captain america, winter soldier, iron man, and war machine's infinity war uniforms, they are the strongest characters you can get bios from story mode.
Are you f2p? If not I would say keep stark stash running year-round. T2 iron hammer as quick as you can because he is the strongest "free" character right now although sharon rogers may outpower him next week. Stay updated on tier lists and dont get useless uniforms. Learn the card, obelisk, and uru systems when you get high enough. Focus on ignore defense and skill cooldown when you start building cards/uru. I do pay and heroic quests are the best crystal payout after stark stash.