I'd say 10/10. What else is there to say apart from have a shave, dress appropriately, wash the van and make sure you have some business cards with you.
It's always self belief. I have every belief in myself whenever I happen to knock. I only knock a few select places but I find selling myself easy. Potential customers aren't stupid they can see if someone is confident and assured, who is comfortable in their own skin. Customers will prefer that character to one who is shady, unsure of themself, won't make eye contact and tries to bluff rather than talk and respond with experience.