Spend time understanding the business you want to be in. Apprentice in that field, so that you know how the business runs and what you would do to enhance your offering.
Make sure you set up your business properly with state and government licenses. Have a Bank, and a form of bookkeeping established. A great resources is the SBA (Small Business Association) which has great resources for learning about and working with you as you start and grow your business.
If you can, have a mentor or advocate in the business you are doing. They are your competition, but have gone through the hurdles that you will experience already.
The key to being successful in business is to avoid planning at the last minute. Spend enough time in planning your activities to kick start your business. Do not ignore risks that are associated with the business you are st rating, reach out to a mentor who can help you in that relevant business. One other factor is your numbers to be recorded black and white and do not defer any business record maintenance.