Hi Rachel!
I recommend you start by finding out where your target market (the people who want or need what you make) hang out online or in real life. Get to know them and find out if what you are making is something that will sell well at the price you need to charge.
For example, if you were wanting to sell cloth diapers, you'd want to find some attachment parenting forums to hang out in and get known in.
Once you know for sure that your potential customers want or need what you're selling and are willing to pay you what the item is worth (in terms of how much labor and materials you have put into it), then you need to look at putting together a brief business plan. This will cover your vision and mission for the business, the strategies you'll use to grow the business and the actual work that you'll need to do.
Generally speaking though, you'll need to determine which shopping website (etsy or ebay, etc) has the right target market for your product, or if you need a website of your own. You'll need to file, at least, a trade name report with your state, indicating the name you will be doing business under.
I'd also recommend you speak with an attorney about legalities you'll need to consider.
You'll also need your state and federal tax IDs.
Those are just some of the beginning steps.
:
