Might try doing 3 sets of reverse curls, a very over looked but outstanding exercise (elbows to the side throughout) and than 3 sets of regular BB curls but only bring the bar half way up and than down again.
The one and one half system gives good results as does the three grip EZ bar curl. Two sets extra wide, two sets middle grip & two sets close grip (4-6 inches). Try running the rack for two cycles, this will really affect the biceps strongly. Not to many people will bitch about not being sore the next morning after that one. Though soreness has nothing to do with muscular growth. Most arm systems can be done twice or even three times a week. Good Luck.