Tipping In Spain
Tipping is generally not done in Spain, especially by locals. Visitors, especially in cities and more touristy-areas, are expected to be a bit more generous and often leave a tip or Propina.
In general, you can simply round up your bill to the nearest Euro whether you are in a bar, cab, casual restaurant or getting a haircut.
If you are in a nice upscale restaurant you could leave a 5-10% gratuity. Some higher end restaurants have taken to adding a 10-15% service charge to bypass the issue entirely. Look for servicio incluido or service no incluido on your bill to guide your tipping decision.