[OMFG!You'reActuallySmart!]

For cleaning, baking, dog-walking and whatever else, the best way would be advertising, which in this case involves lots of signs, spreading the word around your community and getting your parents to see if they know anyone who would be interested. At first, stay near your house so you can get some practice from people who know you and are going to be more receptive. If you find it isn't going well, then time to cut your losses, otherwise continue forward. Phoning people isn't always a great option simply because they're often pestered with enough similar phone calls as it is.

If you use public facilities with lots of people, such as churches, then you'd want to ask the person in charge if they will allow you access. Unfortunately, people are greedy so you need to protect the money you make, which would be best achieved by getting at least 1 other person to help you out. The best option would be an adult from your family because they're probably not going to want a share in the profit, so it'll be all yours.

Alternatively, you can go door-to-door or have signs out that people can call, and make a schedule of the houses you'll visit to sell baked goods, clean their house, etc... . The only issues with this are you need suitable transportation and be on time. We're in the process of getting estimates for part of our roof to be re-shingled and it's frustrating when the person is late, especially if they don't call to warn us.