1. Are you an agency or a solo developer? If it's just you or you and a friend or two, you might get a better response building up your personal brand rather than representing yourself as an agency.
2. I can't judge your technical chops, but I can see that you have room to grow in UI design. I like this youtube channel: https://www.youtube.com/user/DesignCourse, but there are tons of design resources available.
3. You might need to focus more on sales. Is there a small business you like that doesn't have an online store? Call them, email them, go visit them in person- try to make a sale. You could offer the work in exchange for products at first- once they are happily selling online, they will tell other business owners, and you can get more referrals and raise your prices.