You could try using a e-z curl bar instead of dumbells...
What helped me was to do more things with my non dominant hand. Such as house hold choirs?
Just try to pay attention when you are using that arm?
-------------- We must take care of our bodies, its where we live.
Other way around. Use dumbbells and perform the set with your weak arm fisrt and then perform the same number of reps that your weak arm did with your stronger arm. Do this for all one arm work. Do 1-arm DB shoulder press. Do 1-arm pushdowns, curls, raises, anything that your weaker arm can do by itself. Then repeat the reps and weight for the given exercise for the stronger arm. Your arms will eventually even out.