We are 1 (web/backend/php) dev and 1 UI designer with each over 9+ years of experience. We recently left our jobs (Mega.co.nz and SF Stealth Startup) to start a dev & design studio to help startups.
Go out and talk to your prospective clients. I Can't stress this enough. Talking to your prospective clients is the best way to learn more about them and how they made decisions of which freelancer to choose.
When you meet, make sure that you look like an expert in what you do. :) This alone got me quite some clients.
My learnings:
1.) Try to engage with customers on retainer basis
2.) Approach other design agencies or development studios
3.) Attend local meetups/hackathons and conferences
4.) Contribute to Open Source
5.) Don't rely on Google or Website leads
6.) Approach customers with specific solutions, help them understand the value of good design. Send them POC
7.) Approach clients similar to what services/ products you earlier delivered
8.) Talk with your friends
9.) From your contacts Facebook, LinkedIn etc. create influencer list and talk with them once in a month
10.) Send me good wishes and some money if this helps you :p