I've been looking at my play recently and I think I miss out on a few spots by not betting the river, so after a few pointers if possible.

Say I raise QT on the button, a limper calls and I am heads up.

Flop is Jh 4c 7d

He checks and I make a standard c-bet of 75% pot.

Turn is 2h and he checks, I check after.

River comes Ac, he checks, now would it be profitable in the longterm to fire a 75% pot bet and rep the ace?

I know checking after the turn was weak but my range definetely holds an ace, so would that be a good spot to steal?

So often, I fail to make the river bet and a hand like 66 takes it down so I'm thinking betting the river when an overcard such as K/Q/A hits the river to rep QK/AK type hand?

I play NL20 so you do see some crazy calls on the river so just wondering whether I'd take it down enough times to make it profitable?