Find the subject, or who or what is performing the action, and the verb, or action the subject is performing, of the sentence. For example, in the sentence "My dad sent me a birthday card," "dad" is the subject performing the action of sending, as determined by the action verb "sent."
Ask yourself who or what received the action of the verb to determine the direct object. For example, in the sentence "My dad sent me a birthday card," "card" is the direct object because it is the object dad is sending, or that is receiving the action of the verb "sent."
Determine the indirect object by asking yourself who or what received the direct object. For example, in the sentence "My dad sent me a birthday card," "me" is the indirect object because "me" received the card, or the direct object, and is to whom the action was performed.