My biceps have always seen good outer growth from doing hammer curls. There are two ways that I like to do them:
1. Dumbell Hammer curls, when you keep your palm facing your body throughout the entire movement from start to finish. This is a great pump!
2. Grab a cable machine, where you normally would do cable crossovers or something, and set it on the bottom knotch.......do not put a connector on it, but instead, grab the ball that keeps the cord from sucking up into the pulley, and do the same movement keeping your palm close to your body.
If you want to gain a good peak on your biceps, get in the center of a cable machine, & grab one side with each arm. Make sure the cable is set at the highest setting. Now, pretend you are going to flex and keep your arms parallel to the ground, going back and forth. This is my finishing bicep workout.