Strength is king. First you get strong, then you get big. Doing 10-12 reps of curls will give you some sarcoplasmic hypertrophy (aka: fluid and increased glycogen storage), but it has a multiplier effect. If you have little or nothing there, you will make little or nothing grow. Instead, try for myofibrillar hypertrophy which is growth of the actual fibers. Reps in the range of 5-8 can accomplish this, however, you're better off doing Strong Lifts 5x5 or Starting Strength. Feel free to start customizing your workout when you can bench 225, squat 285, and deadlift 315+ for 3 sets of 5 reps