Transportation and restaurants seem to be two different animals. Taxis, taxi-vans and boda bodas(if you are brave enough) generally don't expect tips, and always get a quoted price upfront for your trip.

 Most servers at local restaurants will be happy with 10%, but if you liked the server and plan on going back to that establishment again, go ahead and tip like you would in the U.S. Doesn't necessarily guarantee good service, but chances are very good you will have servers vying for your table.