This is the executive summary of what to do.
First sit down to your computer or a pad of paper and define your business in writing. In doing so, understand who is your customer, an art director, a small business owner, or a Mom. Then write so they can understand who you are, what is your business and most importantly how you will make their life better.
Find out who will be your competition. Get all the intel you can on them. Look at their work, research their pricing and determine how you compare. Be prepared to tell your prospects why they should buy from you!
Pour through all of your images to build a portfolio. Build your portfolio into market segments you plan to penetrate. You may think you want to attract a particular market segment, but have no samples of that work. Maybe you shouldn't market to those prospects or build your portfolio to support the market.
Create your brand. That includes business name, logo and tag line to start. After you've created those items prepare to incorporate them into all your promotional materials.
Research and fully understand all your costs. Build your pricing structure based on where you plan to position yourself price-wise with respect to your competition. Now compare your prices to your customers with your projected expenses. Figure out if your market can support your expenses, make a living for you and decide if things are viable.
Find 3 to 6 business minded people and ask them to read what you've written, and assembled, then ask for their feedback. Then go back and edit to their feedback. Have them re-read the material to make sure you understood them.
That's the short version! Good Luck.
Now go find a website template and fill in the blanks!