Try using some chalk for your heavy pulling movements, you'll soon develop the strength in your grip.
I've used some before, and I did love it, but the old gym didn't like it. One I'm at now though doesn't mind, so I'll get some again.
Wrist curls won't do anything for your grip.
Static holds
Plate pinches
Farmers walk with DBs
etc.
Things like those grippers you can buy aren't great either. Static holds is what sorted my grip out, I went from struggling with 190kg deadlifts for reps to holding on to 260kg in a rack for about 20 seconds. This only took about a month 18 months ago, and I've not had any problems with grip since.
Got it. I do farmers walk with plates/dumbbells on leg day. I'm definitely going to add the static holds and plate pinches in though, thanks dude