Have a beer and have at it! LOL No disregard that comment. Hehehehe like Sprink said the down part can be scary! Remember to bring the throttle down as she starts going into the down part because the plane will start going faster and obviously she will most of the time start rolling faster as well. Also rember to start bringing the throttle back again when you start heading towards horizontal again. Do not fuss too much with getting the rolls axial by using rudder on the first couple of attempts. I did my first one using only elevator, aileron and throttle. Like sprink said don't use a high rate for it in the beginning, try a lower rate for the ailerons so you can keep track of what's going on and then work the elevator timing. It will be good to practise rolling circuits and figure eights as well.

EDIT: And sorry but I didn't quite answer your original question. The best technique I can think of now is to use all three control surfaces as well as manage the throttle properly. In order to get a clean axial roll you will have to combine rudder and elevator inputs to get the manuver clean. Also you would want to exercise different aileron inputs when the plane enters different stages of the manuver to try and keep the roll rate the same throughout. Meaning you will have to sometimes reduce aileron input when the plane enters the down part of the manuver so a constant roll rate is achieved.