Indirect object pronouns are some times a challenge. One way to distinguish them from direct object pronouns is in this manner.
Most sentences with indirect object pronouns include a prepositional phrase and a verb that indicates communication.
Gino spiega la lezione a Giulia.
(Gino le spiega la lezione.)
le = indirect object pronoun.
Most sentences of this sort contain verbs of communication:
Hope this helps all who find this a challenge.