I would advise against getting a California Contractor's License. Keep your jobs under $500 and you're golden, even if you go over, it's no problem because nobody's policing this. Anything that requires a license, refer to a friend who is licensed and get him to pay you a finders fee. Never use a contract, and get money up front for each phase of work. Get cash or if you do get a check, cash it at their bank, don't pay taxes.
Always do good work. Never document anything and never pull permits or buy insurance. This may sound like bad advice, especially coming from a licensed contractor, but I know plenty of UTR (Under The Radar) unlicensed contractors who make 6 figures and their only overhead is their cell phone.
28 years ago, when I became licensed, that was the only way to really make money, but things have changed drastically since then. If you stay lean and mean and hustle, it's all gravy.
Best of luck!