I started working out more than a year ago but am still not very happy with my biceps .... I used to do 3 exercises with 8 reps each until very recently when alot of ppl told me that I was over training my biceps. I always train my biceps along with my back. SO now I alternate between two bicep exercises (8 reps each) :

1. Barbell curls
2. Preacher curls

OR

1. Inclined dumbell curls
2. E-Z bar curls

I try variation, I lift heavy and I pay strict attention to form. Hell what am I doing wrong??????? please advice

Try concentration curls with isometric holds on your last 2 sets of your last bicep exercise (concen. curls)

I like straight bar curls and hammer curls.

For biceps I do close grip pull down, close grip standing rows and some EZbar curls

Are you growing elsewhere?

Yes I am ... my shoulders, chest, triceps, back ... its just the biceps that I am not really satisfied about.