Hi! Well, accents -in Spanish- have their rules, and there are quite easy to remember...
Words stressed in the third from last syllabe ALWAYS have accent. For example, "sÁbana" (sheet), "mÚsica" (music), "Ébano" (ebony), etc. It doesn't matter if before the third from the last syllabe there are more syllabes (for example, "inalÁmbrico" -wireless).
Words stressed in the penultimate syllabe have accent only if the word doesn't end on n, s or vowel. For example, "cAsa" (house), "mAnos" (hands), "mIran" (they look), etc. Otherwise, they have accent: "Árbol" (tree).
Words stressed in the last syllabe have accent only have accent (keeping in mind the previous rule, by its opposite) if the word DOES end on n, s or vowel. For example: "canciÓn" (song), "atrÁs" (behind), "amÓ" (he loved), etc.
There are exceptions when it comes to monosyllabic words. Accent is put to distinguish between two words which, though they are written the same, do not mean the same. For example: "te" (personal pronoun for "you", as in "I see you", "Yo te veo") and "té" (tea); "más" (more) and "mas" (but); "si" (if) and "sí" (yes), and so on. They are pretty few.
Hope it helped!
One more thing: interrogative and exclamative pronouns, as well as diphthongs, have different and more complex rules. I'd love to explain them to you, but I'm not quite sure about how.