tu and ti
when do I use tu and tI???
This requires a rather long bit of explanation: So let's start with the the basics of conjugation. Every verb has a subject. The subjects are (yo, tú, nos, él/ella, and ellos/ellas). Subjects are used with a conjugated verb for clarification or emphasis.
Belle: He's no monster, Gaston. You are!
Belle: No es ningún munstruo, Gaston. ¡Tú eres!
Tu without the accent mark is a possessive adjective. It is used to say things like:
Tu casa - your house
Tus hermanas - your sisters.
Sometimes it can be used as "tuyo" in sentences where it doesn't precede the noun, such as "Un amigo tuyo" or "Los gafes son tuyos."
Tí on the other hand is a personal pronoun. It is used in sentences like:
A tí, te gusta bailar?
Feliz cumpleaños a tí.