I don't canvass much nowadays - maybe occasionally knock on a couple of doors around a new custy but I used to do one of three things.
1. Smart casual trousers, V - neck jumper smart shirt but no tie.
2. On really big houses or businesses - suit jacket and tie but with smart trousers of different colours so not as smart as a suit - think head of geography dept. teacher (no leather elbow patches though!

)
3. Workwear jacket, poloshirt and working trousers.