Here are some tips for web designers from Steve Snell on Factors to Consider When Pricing Design Services. The points he makes are consistent with the experiences Pelago has had as a small web development shop. However, there are a few other things to consider.
When considering how much time it will take (factor #1) it is helpful to have tracked your time on past projects. As your business grows you will find yourself working on several similar projects. Knowing how much time those projects took is invaluable for pricing future projects. You can track your time using a web-based service, like Intervals, or keep records for each project on a notepad. Either way, make sure you are taking note of how long your projects take to complete.
When considering outsourcing (factor #12) our advice is don’t consider it at all. Stay away from any projects that are going to require you to sub parts of it out, especially those projects that require expertise outside of your abilities. To be successful as a freelance web designer you need to focus on your strengths. Trying to manage others, and getting them paid on time, is going to distract you from doing your work.