For this exercise, you will want to find a bench and a relatively heavyweight dumbbell that you can curl with one arm. Sit down on the bench and pick up the dumbbell.
Rest your elbow on the inside of your leg, extend your arm while still keeping your elbow on your leg and curl it back in a concentrated and controlled manner.
You should do this for each arm, generally 3 sets of 10 provides a sufficient workout for each of your biceps. This exercise is unrivalled in terms of at-home isolation movements for the biceps. Do it regularly to sculpt more symmetrical biceps.