A simple but very effect bicep exercise using dumbell can be utilised with greater effect by changing the grip and also rotating or twisting through the motion to gain a greater emphasise on the shape of the bicep. Always control the body upright not allowing the body to sway as the bicep will be used to greater effect if it is doing with exercise solely with no other assisstance by not using momentum. Breath on the way up or the concentric phase. Hope this explaination helps to progress your workout. Just remember it is not about how much you can lift but by the way you lift it will give your far superior results. Enjoy!