THE BEECHMONT CREST SPANISH STUDY GUIDE:
Some Rules for Accent Marks
In written Spanish, an accent mark (acento or tilde in Spanish) appears only on a vowel, as in la Península Ibérica (the Iberian Peninsula.)
An accent mark also distinguishes pairs of words that look and sound alike, but in fact have different meanings and functions:
qué = what / que = that
cómo = how / como = as
sí = yes / si = if
mas = but / más = more
mí = me / mi = my
te = you / té = tea
tu = your / tú = you
el = the / él = he