David718 - you are getting good advice here.
Especially what Tilen Krivec said - that is spot on. You need to show businesses that you are established, and proof of your past work accomplishes that. Then, everything Tilen said about VALUE is 100% correct - and I know that based on experience. Take his advice.
Also, similar to what Ava said- be flexible in early compensation. Be willing to show them what you can do before you expect to be paid. This removes barriers for the prospective client. You want to take away all sense of risk for that business, especially to get your foot in the door. If you show them what you can do first, if it is really valuable, then you are home free from there.
If you are a one man operation, you should consider concentrating on a few businesses, and doing well with them. Don't spread yourself too thin. If you are doing a good job with the clients you have, you'll find that you won't need advice on how to get new ones. :-)