Here's a brief guide to tipping in Spain and Portugal. Tipping 5% - 10% maximum in restaurants is standard, although tipping is only done if you are happy with the service. No tip is expected for a cup of coffee or a drink, although some people will leave the change rounding up from the nearest Euro.

Tipping in Portugal is just as important as in other parts of the world.

All waiting staff, attendants and clerks earn a wage, but  wages are low and many do rely on tips to supplement their income. In addition, many, many such workers rely on social security out of season, so they have to work very long hours during the summer.

A service charge or serviço is NOT usually added to hotel and restaurant bills in Portugal. However, it is customary to tip an additional 10 % if the service warrants.

The bill at the restaurant only charges for what you eat; it is customary to leave a tip 10% + (the amount depending on the quality of the service you receive ).

In hotels, tip €1-2 for bellhops who carry your luggage up to the room.

You may also add €1 per day for the maid who provides extra service - such as bringing breakfast to the room. (You may also consider leaving them your holiday toiletries. It's less weight for you to carry, makes more room in your luggage for souvenirs and the maids are always very grateful.) 

Taxi drivers can be tipped by any amount you wish, although some people round the fare up to the nearest five euro (ie. your fare comes to 7 euro, you may wish to pay the driver 10 euro). This is particularly true in Lisboa, the capital.  Some people add 10% of the fare as the tip. 

In the North, tipping of taxi drivers is less common or generous-- in Braga, a 10% tip is considered generous unless the driver has helped carry bags, etc., and in some restaurants and cafés, you may find the owner chasing you down the street to return change he thinks you've inadvertently left on the table!

Etiquette

The Portuguese and their language are very polite - you will hear 'please' (por favor or se faz favor), 'thank you' (obrigado/obrigada) and 'my pleasure' (de nada) as much as you will hear  similar in England for example. It's customary to say good morning (bom dia), good afternoon/evening (boa tarde) and good night (boa noite) as well as good-bye, cheers etc etc!

Snapping your fingers or shouting at waiting staff or bar staff will usually have just one result - you will be considered rude and be ignored for a while! As it would be in most countries.

The people are very helpful, especially in the tourist areas, eg. the Algarve. Their living depends on it. English is widely spoken, especially by younger people, but it is polite to first ask  "Fala inglês?" (Do you speak English?).  Don't speak to Portuguese people in Spanish. Many don't like it, for historical reasons.

French is often a second language.

But, on the downside, Portuguese don't normally form queues (stand in line) as do some nationalities and when it comes to car parking, it's a free-for-all except for in Lisboa, where it's simply impossible.

Some side notes-- the Portuguese are very honest, as well as very helpful-- outside of big tourist areas such as the Algarve and Lisboa, people routinely leave their umbrellas outside store doors to keep from dripping on the floor, knowing that they won't be stolen, and a woman can leave her purse on the table when she goes to the restroom and expect to find it there on her return... not true everywhere in the world. Still, crime is on the rise. It is best to not leave your things unattended.

Do not take risks which you would not do at home such as walking around alone at night ,as it is not unusual to be followed by unsavoury men,  witness violence or be approached by drug dealers and prostitutes in tourist areas. If you ask directions on the street, you are likely to be walked to the place you're going if the Portuguese person doesn't think you understood the answer-- even if he or she was headed in the other direction!  [That may explain why the American/northern European's expectation that a 3 p.m. meeting will actually start before 3:10 or 3:15 is frequently not met...]

Entertainment starts late here.  A concert (and not just about rock-- also piano concertos and plays, etc,) will routinely be scheduled for 9:30 p.m.... and may not start on time.  No one minds, and it's important not to act impatient as a visitor, as it may appear to be critical.  This comes as a shock to North Americans, but this is a country where people don't go to bed until much later-- many restaurants don't even open until after seven in the evening! 

Source : Tripadvisor.com