A knowledge of Spanish will enrichen a trip to Spain, but you can get by perfectly well with English in the major destinations. Spaniards are in general friendly and tolerant towards foreign visitors.
Here are some useful phrases in Spanish:
hola - hello
buenos dias - good morning
buenos noches - good evening
buenos noches - good night
adios - good bye
por favor - please
gracias - thank you
perdon sorry / excuse me
Una cervesa, por favor - One beer please
Otra de lo mismo - Another one please
La cuenta, por favor - The bill, please
Soy vegetariana/o - I am a vegatarian
Busco un hotel barato? - Where is a cheap hotel?
Donde esta la estacion de autobus? - Where is the bus station?
Donde esta la estacion de tren? - Where is the train station?
Donde esta los servicios? - Where is the toilet?
Hablas ingles? - Do you speak English?
Si - Yes
No - No