You can build bigger biceps by bending your wrists slightly when you are doing arm curls with dumbbells. When your doing your arm curls, extend the wrists backwards slightly, and hold them like that. This slight change of movement will make your biceps work harder, thus, building bigger biceps.
Fitness is a fascinating and exciting world that is only limited by the extent of a person’s limits. There are endless possibilities, products and techniques. Start experimenting to find something new for yourself or to learn something new that you can better for your own usage.