Leaflets are important, but knocking on doors and talking to potential customers face to face is the best way of canvassing a new round. In my experience leaflets have a very poor take up/response.
Before you start, can you clean a window? Have you practised on your own home and family's homes? You need to understand the basics of using an applicator, a squeege and detailing so you do at least look a experienced professional window cleaner.
If you are going to start traditionally, then practise using a ladder, raising and lowering it, positioning it, climbing and descending it, as well as walking around with it without knocking things, eg., satellite dishes.
If you are going straight onto the pole, then that also needs practise on how to use it correctly. Using an applicator and squeege is still an important skill to acquire, even with wfp.