Picture the figure 8 as 2 clockfaces.
It doesn't matter where you start the first circle but it does matter where you transition to the other one.
lets say you are flying a figure 8 so the the center of the 8 will have the airplane coming at you.
You are to your left in a right hand bank making a right hand circle, when you get to about the 1 o-clock position you start coming out of your bank so that when you are at 3 o-clock your wings are level, don't let go of the ailerons yet, you will roll into a left hand bank so the you are into the bank by the time you get to the 7 o-clock position of the right hand clock face (strait accross from the 5 oclock position of the first circle) the positions will vary slightly according to how fast your plane can transition.
trainers are a bit slow on the ailerons, I can wait till the 2 oclock position to start transitioning in my RV-4.
I hope that makes some sense and helps you.