There are only five vowels in Spanish, and they are always pronounced in the same manner.
ɑː
ɑː is always pronounced like “ah” (as in “father”)
| fall | apple | shallow | app | 
e
e is always pronounced like “eh” (as in “egg”)
| elf | eleven | felt | bell | 
iː
iː is always pronounced like “ee” (as in “police”)
| shift | list | fill | beach | 
oː
oː is always pronounced like “oh” (as in “vote”)
| photo | pole | told | home | 
The O is always a long O. The long O is often the hardest vowel to keep straight.
uː
uː is always pronounced like “oo” (as in “flute”)
| foot | full | true | hoop |