my arms aren't massive but they are decently big for my size. I've read thousands of threads as well as worked out myself using the key exercise as barbell curls. It's a mass builder. Do:
- 3-4x8 of BB curls
- 3x8 of incline DB curls
-3x10 hammer curls
Don't need more than that, your arms aren't large muscle groups, you get work on them with other muscle groups such as back (bi's) exercises.