Biceps is one of the moves where its just easy to go through the movement, and you think you're working the muscle...but you're not.
When done right, you'll get a sick burn when you squeeze them a the top. I like standing cable curls lately, squeeze at the top 2-3 seconds, and lower slowly all the way down to get a huge stretch in the bicep.
Just concentrate on using the bicep, the rest will follow. Don't be those idiots in the gym curling heavy dumbells just HURLING the weight up, first of all it doesn't do shit, second, you look like a tool.
Good luck man