I'm not a professional game developer, but one solid piece of advice -- which makes sense, but many don't seem to follow -- that I keep on hearing (and also am a proponent of) is the following:

Focus on finishing games. Don't aim for the sky with overambitious projects. People who look at your resume will definitely hire someone with 10 completed smaller projects, rather than the other person who has 30 unfinished projects. Completing and polishing a game is far more important than an unpolished game with more features than the former. In summation, it's completion that counts. :)