Following the simple steps below you will have all the tools necessary to gain peoples trust, attention, and support. You know that your cause is worthy, so stand up and do something about it.
Step 1: Preparation
Get a notebook, and a binder. The notebook will be great for writing down names and addresses of people who are strong supporters or people that want you to follow up with them.
Keep a sheet of statistics, facts, and figures that you will not be able to remember, so that when you are asked a detailed question you can show that you know what you are talking about, and you will have sources and information to back it up.
Find some happy music, and listen to it while you are in your car (or on your way to canvass), and while you are getting your statistics together. You are about to be ignored, yelled at, debated, criticized, put down, and many other bad things, and you need to have a cool head, be able to smile, and thank the person for their time.
Find a friend!! This is the most important step of all -- Having one person is not only dangerous to you, but can also hurt your cause if someone claims that you have done something to them, and you have no witnesses to back you up.
Form a plan of action, you can just go willynilly wherever and find people, but its best to target locations that people like you would hang out. If I am petitioning to have the ten commandments removed from city hall, I am not going to start canvassing near a church. If I am canvassing for saving the trees, I would go by a coffee shop, because hippies love chai tea.
Finally, go find some cloths. Some groups will supply shirts, or have shirts that have their name printed on them. This is a great option, however, if you cannot afford the shirt, or your cause does not have a brand behind it... just wear something nice: Collared shirt, slacks, and a tie for guys. Mid-length skirts and blouse for the girls.