So let's stay focused on technique! Now, there seems to be a bit of dissent as to what "forward" and "balance" are defined as here; for my money, "forward" means a willing forward impulse, meaning the horse has his "engine" engaged and wants to go. This is NOT to be confused with speed, or actual "gait over the ground." What we are very specifically NOT doing is putting the horse into a trot or a canter and then trying to balance him after the fact when he starts out on his forehand. We balance him FIRST before initiating the upward transition. Here are the signs to look for:
Relaxation of the jaw
Elevation of the withers (rocking his weight back)
Engagement and willingness to move off your leg
Notice we are not looking for "firm contact" here. Do not EVER confuse this state of "between" hands and legs as "behind the bit." "Behind the bit" is actually "behind the leg," e.g. "sucking back," and not at all a light horse who is willing to leap forward off your spur if you asked him to.