Hi Olive,
With the exception of gratuities to hotel porters (one piece of luggage per person), tips are not included in the price of your holiday and there will be occasions when you are expected to tip.
When calculating the tip in restaurants and bars, 15-20% of the bill is usually appreciated, sometimes the tip is added to the bill and when in taxi cabs, 10% of the posted fare is usually appreciated.
Hope this helps,
Kind regards,
Julia