Create a detailed business plan. Determine the scope of services, how you will advertise and market, licenses, permits, insurance, employees, accounting, staff, etc.
Make something from wood maybe furniture or a ornament and advertise it. Get your business a name put it in your local paper. Find somewhere to show off your wares that you have created start off cheaply to get things started.
If you want to start a legitimate business, you're going to need to get licensed as a contractor. Each state has a board that will evaluate your experience to make sure you qualify. Then you'll need tools, insurance, and an advertising plan.
The requirements for starting a business vary from state to state and for the dollar amount of business. Look up the requirements for Contractors in your state or post again.
First a good and neat place is needed. And you should be social with friends and relatives that you are going to start the carpentry business. Buy branded tools and wood in good quality.
Hire out as a general handyman or repair helper, whether cutting firewood or sanding down decks. When you have serviced these customers - who are now happy with your general skills - inform them you can do more complex work, as well.
You are going to have to be licensed probably through the city and then you can start your business and advertise through the paper or TV to get customers that pay.
