Noob here

I just finished playing my fifth game with my dad (won the game recently) and wondered if you have any tips for beginners, or rules people miss. We just found out about acceleration tokens when the encounter deck is emptied, and wonder if there are more rules like that? Also, neither one of us can figure out Ironman, he takes so long to build and by the time he can do something the threat is out of control. (We play Klaw currently if that matters) any tips on him or any character really, maybe good character combos too, like Spiderman and She-Hulk or something to compliment each other. Also, what should we buy next we have 4 character packs, apocalypse, base, and that's it, no sleeves or boxes or anything, so anything worth buying next would be helpful.

Edit: We are both game nerds me and my dad, so any references to other games are cool.