Some great advice on here. Besides what has already been mentioned, you would be wise to set up an LLC or other structure (s-corp, c-corp) to separate your personal assets from the liability of the business.
You file separate taxes. Separate checking and credit cards.
you need an EIN. If you don’t know what that is, then you are most certainly not ready to set up a business.
It’s not just a question of income and expenses. Don’t forget about depreciation. The first few years I ran my business, and did my income expense report at the end of the year, thinking I had made a profit and sent it off to my CPA … the depreciation on assets put me into the Red.
We were just really starting to turn a profit… And then Covid hit. Income dwindled. I had a discussion with my CPA as we had been in business for five years and we decided to force a profit by not taking quite a few expenses.
Here in California, you pay an $800 annual franchise fee whether or not you make a profit or loss. You have to make annual statements to the franchise tax board. I’m sure other states have similar types of requirements.
If you are not prepared to do all of those things, then it is a hobby.