Its a small muscle group so hit them hard intense and fast from every angle, hit the middle and lower biceps but make sure you go to your absolute limit. Once that pain starts flowing through your arms and its triggering that response in your brain saying fuk this ive had enough, you don't you carry on and drop set, rest pause or forced and negs and explode those arms.
Straight bar curls or seat db curls and make sure you squeeze those fukers at the top, don't stop and make sure you go round down to halfs and quarters,
Incline db curls, this will target the lower bicep so when your arms are hanging down straight by your sides they bulge out, this is a remarkable movement to give a great illusion of size,
bent over concentration curls keep your elbow stationary and do these standing up, squeeze and slightly turn the bell outwards so your little finger is slightly higher than your thumb, this fuks your arms up and build immense peak and thickness
Mind set and motivation to go past failure is always the key to further growth