Tips are very common in Asia, but not generally in Myanmar. For waiters, luggage porters, maids, bus drivers, taxi drivers and tour guide gratuities are a nice addition to their meager wages. Small gifts are appreciated, such as pens, cigarettes and perfumes. Burmese are fond of Western music which is usually difficult to obtain in the country, so bring along your old cassette tapes that you're no longer using. Foreign T-shirts do wonders. Keep offering presents but note that initially they will be refused. That is polite. In simple restaurants or food stalls along the way, tips are not usually expected.
The bus driver expects a tip for the time in which they drive you, at least if they have done their work satisfactorily (guideline: € 0.50 per passenger per day). This also applies to the tour guide, of course if she/ he has done well. Our guide to this tip is € 1 per passenger per day.