You only need to use rudder when doing slow rolls. With quick rolls, a bit of down elevator when inverted will correct the flight path. You may need a little bit of up elevator when you level off having done the roll, or if you are doing a double roll.

Virtually all planes will pitch towards the ground as you do the roll as you are no longer flying the right way up, the wings are working with gravity rather than against it.

A good practise for rolling is flying inverted. you will learn how much down elevator is needed to keep the plane level when inverted. In the roll it then just becomes a matter of timing.

To practise slow rolls work on knife edge first in the same way.