One hint to help without having to do extra sets of
arm exercises just for forearms - and perhaps to clarify my reasoning from my previous post.
When I do
dumbell curls, I do them standing - bring the DB up like a hammer curl, rotate it into a full regular curl at the top - then twist the wrist out at the very top of the movement and curl it down toward the forearm. This works the bicep for width, heigth, and peak. It also gets the forearm.
When I do skullcrushers, when I bring the bar down to the top of my head, I then "reverse curl" my wrists at the bottom of the movement. Then at the top, I curl them forward.
On my arm day, my forearms get well worked while doing my regular arm work. Of course deadlifts, pullups, lat pulls, etc... also hit them too.
My left forearm is slightly behind the right since I'm a right handed person (left bicep too). I correct this by loading and unloading the bars left handed. When I load my dumbells, I hold the dumbell out in front of me with the elbow resting on my thigh...again more forearm work without having to add extra exercises.
However, if you need them or have the time - do more.