Start with practicing a few shots with all the weight on the right leg the whole time. Just balance with your toe of your front leg to keep you from falling down.
Then hit 2-3 with a normal setup still thinking of the drill. You will feel the exact same position in teh back leg.
Then there is the "Screw" thought. Imagine your back leg a screw as you go back, it drives into the ground slightly (this is mainly to keep the flex the same, but is also works to help in the weight transfer).
Then there is the thought of placing your leading shoulder directly over your trailing knee at the top. This is something to help both shoulder turn And weight transfer.
And the last one, is my
walking drill. If you do this AND walk the straight line without falling, you have proper weight transfer.