If you go into the difficulty menu, you have the option to double your awarded EXP per battle. I didn't discover this until a few dungeons in, so I want to pass the wisdom onto you as soon as possible, because it somehow makes the grinding even more rewarding.

I can't trust Teddie. I've met Monokuma and I am programmed to be suspicious of weird bear mascots. (ALSO TEDDIE DON'T HIT ON YUKIKO, WHAT ARE YOU DOING)

Teddie... legitimately fills me with despair. And that's all I'll say for now.