Local Tour Guides - Getting more business

This week I would like to discuss and get feedback on how local tour guides can get more work and therefore income.

Tour guides can join with a local travel agent
Tour guides can join websites e.g. www.ourexplorer.com
Tour guides can market directly themselves in hotels, tourist information offices etc

All these options carry advantages and disadvantages varying from cost of commission, cost of entry and volume of business received.

I would like to hear from tour guides on their experiences with the three sources above?