My arms have grown around 1.5" in the last six months. Here's what I did:
1. Put on around 8-9kgs in bodyweight (97kgs to 106kgs) and then gradually worked down calories to maintain weight around 103kgs.
2. Did a lot of heavy pressing with regular grip.
3. Did a lot of heavy close grip bench, mostly from boards to allow higher weights.
4. Did a LOT of triceps volume after heavy max effort work. Normally doing 100rep's total of some form of isolation in as many sets as it took, normally between 5 and 10.
PS: I don't really train biceps so you know that most of that 1.5" is tri's