Can I learn myself a proper punch?

So I joined MMA gym, but it's mostly grappling with very little striking. Trainer told me do some basics at the bag and stuff, I even did a little sparring, but got little feedback(aside from advice to stop tensing up, although they taught me some combos aswell)

I wonder if there's anything I can do at home to learn how to strike better

I'm not sure if it's about lack of practice for me or if there's something very basic I don't understand about striking