Check this link out http://www.talkenglish.com/Speaking/listTravel.aspx

sorry,actually i can not understand your mean.

Yes, Nicole K. suggests a good starting point, but it does seem to be focused on the United States. In the UK 10% is a more normal guideline for giving a tip in recognition of good service. Sometimes in London you will find that some restaurants add 12.5% automatically, but you are at liberty to deduct this if the service is "not up to scratch"! Just don't add on another tip to it!!! Basically do some research on the specific English speaking country you are intending to visit! Wishing good luck in your studies and travelling!