"I wanted to see you."
Translation:Yo quería verte.
That would be preterito, which would mean the wanting had ceased at some point, which could be appropriate, depending on the story line. "When I saw your foto, I wanted to see you."
If it were an event (the photo example by rspreng is good). Think of the imperfect as being description.
quise verte translates better as I meant to see you (but didn't) or I tried to see you (but it didn't work out)
If it's just in my mind wanting, then imperfect tense