At table service I usually round up, for example if the bill is €14.70 I would give €17.00 Its basically to acknowledge that the server went above and beyond their normal job description, for example if they made an effort to interact with kids, helped with food allergies, made a food or drink suggestion, or something about the parks or Disney etc etc.
Frequently I leave NO tip, its optional , not a requirement! I have NEVER tipped mousekeeping!
Service jobs such as servers, mousekeeping, bell hop, luggage porter, room service, concierge tour guides, bus drivers, taxi drivers etc etc get a proper minimum / living wage in Europe. They do not rely on tips to make up their wages / pay their rent / pay their health insurance etc. You do not need to tip ANY of these!
For example in Europe you will NEVER be chased by a restaurant server who demands a bigger tip. You will NEVER be chastised by a taxi driver and pressurised to give a tip. In hotels, your room will be cleaned to hotel policy and standards without you having to bribe the housekeeping staff with tips.