Tipping is not as common in Spain as it is in some countries. Before you thank the staff, you should carefully consider whether it will be appropriate and whether it will offend the feelings of the Spaniard.
Cafes and restaurants
Spanish law prohibits restaurants from charging additional service charges, and most restaurants and cafes have a sign stating that all service surcharges are already included in the price of lunch. Therefore, tips are not always appropriate.
After drinking a cup of coffee at breakfast and eating a sandwich, you can say goodbye to the waiter and thank him in words. With a bill of a couple of euros, no one will expect a tip. But after dinner, you can leave 5-10% for a decent amount, but only if you really want to express gratitude for the good service.
The Spaniards themselves usually round the bill to the nearest euro when paying, and leave the remaining centimes to the waiter. And if you have doubts about whether to tip in Spain or not, you can do the same. All coins are usually put into a "common pot", and at the end of the working day are divided equally among the service personnel.
Hotel service
When trying to thank the maid with a pair of euros left on the bedside table, the tourist usually fails. The money remains intact, and the service remains at the same level. If you try to stick them personally into your hands, you can deeply offend the person.
The main income of maids, like waiters, is their salary. Therefore, it is better to leave a tip in hotels in Spain only at check-out. If you do not have the strength, as you want to please the hotel staff, you can leave a note of gratitude, or put it in an envelope with money. It would be quite appropriate to give a box of sweets, especially since no woman can resist here.
As for the porters and other staff, who periodically make the stay of the hotel guests pleasant, they can be thanked with a small amount of up to 1 euro.
Taxi ride
The principle of tips in taxis is similar to the situation in restaurants, although it is much less common. If the taxi driver helped to brighten up the time of the trip with an exciting conversation, or was kind in any other manner, you can thank him by paying the amount on the counter, rounded to the next euro.
Perhaps there is only one case when a larger tip is not only appropriate, but also helps to leave a very favorable impression of yourself. For example, if the trip distance was short, but before that the taxi driver had to stand in a long queue. This is common in train stations and airports.