Pronouns always come before the verb in French:
Tu y penses.
Tu me le donnes.
Except for two cases:
In a question with inversion, the subject pronoun goes after the verb and is attached to it with a hyphen:
Y penses-tu ?
Me le donnes-tu ?
In the imperative form, the verb comes first and the pronouns follow (also attached to it with one or more hyphens). Note that in the imperative there is no subject.