My formal education ended with a Masters degree in theoretical physics. The job market is tough for a theoretical physicist so I looked to expand my choices. The natural choice was web development which I studied (on-and-off) for more than 10 years. Now I'm available to build maintainable front-end projects using a variety of technologies ranging from pure HTML(5) and CSS to projects involving javascript libraries such as jQuery, knockoutjs, Reactjs and Node.js. Along the way I picked up enough knowledge of linux, apache and PHP to troubleshoot back-end issues.
My most important rule is to avoid giving an estimated timeline before all important aspects of a task are known. This way both the company I'm working for and I will avoid nasty surprises.