You need to try to make money as you travel - not an easy task. The good part is, there are lots of options. It can be local jobs (if you have a workers' permit/visa, of course) or online. The more creative you get, the more opportunities become available to you. You are only limited by your imagination. If you want to make something happen, you will find a way.
What types of jobs are suitable for a traveler? This post will focus on a few basic guidelines to help you think of ideas and narrow down possibilities.
What you do depends on your expertise - and especially your interests. If you aren't interested in what you're doing, you will get burned out very quickly. Burnout can rain on your parade (I mean travels!) and deplete your funds even quicker. You can only tolerate something so long before you can't stand it any longer. Therefore, the first step in finding an on-the-go job is being honest with yourself about what you enjoy or are interested in.
The second step is writing down ideas. A few to get you going include: freelance travel writing (or photography), blog writing, eBay sales, or any job that allows you to telecommute. If you have a good relationship with your current employer and if it's possible that your job could be done remotely, consider asking your manager or supervisor about telecommuting. Another thing (which is one of my favorites) that can be done remotely once you get it going - is real estate investing. Other offline, local ideas include seasonal jobs at your destination, housesitting, English teaching jobs, and anything temporary (such as waiter/waitress jobs). More on each of these individually later.
Hopefully this is enough to get a light bulb to come on in your head. :)
"Half the fun of the travel is the esthetic of lostness." -Ray Bradbury