We do not use the subject pronoun in the imperative:
Tu vas. You go.
Va! Go.
Object pronouns (me, te, le, la, lui, nous, vous, les, leur) and the words en, y are put - unlike in the affirmative - before verbs, but after verbs, we use strong pronoun forms (moi instead of me, toi instead of te):
Donne-moi le cahier. Give me the notebook.