Tbh i wouldnt recommend doing wrist curls unless you're not at all bothered with getting premature artheritis.

The wrist rolling thing is a brilliant exercise....also the comment r.e. gripping weights tighter, if you try that on any exercise you do you'll definately see the advantages, you'll also get better control over the bar when doing bench, ohp etc.

Also try wrapping a towel around the bar when and if you do chins so you're having to grip harder and wider.

Another one is farmers walk with dumbells or plate pinches (grip work really but will improve forearms)

Finally, try this one when you do barbell curls. Pick a lighter weight than usual, take a regular underhand grip on the bar, then curl all the way up. Do 8 reps doing half curls over the upper half of the 90 degrees rotation (start at the top of the curl with the bar near your chin, lower it down so your forearm and bicep are at 90 degrees to eachother, then curl up again) then do another 8 reps on the other half of the 180 degrees (from the bottom, up until bicep and forearm are at 90 degrees) if you can push out any more, do 8 full reps after that. Theres 1 set done.....feel the burn

Hope that helps, if you cant understand what im going on about with the last exercise let me know and ill try and explain it better.