Tipping at restaurants, bars and coffee shops is optional. A ten percent service charge is already added to the bill. If you feel like service was great, you may leave an extra tip of your choice.

If you stay in a hotel and the bellman takes your luggage to your room it is propper to give a tip. Once in the room you may leave a tip to room service personnel and to housekeeping.

In general good manners as you would apply anywhere in the world, at least in the Occidental world. Always say hello, goodbye and thank you, keep a smile and ticos will be grateful to help.   

It is very proper to say ¨please¨, when asking for something.  Ticos appreciate politeness.