The full set
Object pronouns go right before the conjugated verb.
| me | mi |
| you | ti · formal La |
| him, it (m.) | lo · l’ before a vowel |
| her, it (f.) | la · l’ before a vowel |
| us | ci |
| you all | vi |
| them (m. or mixed) | li |
| them (f.) | le |
Before the verb, after non: non lo compro.
In the passato prossimo, the participle agrees with lo, la, li, le: l’ho vista, li ho presi.
With an infinitive, both work: lo voglio vedere or voglio vederlo.