Breakdown of ¿Qué te parece el plan?
qué
what
te
to you / yourself (reflexive) / you (direct object)
el plan
the plan
parecer
to seem; to think of (what do you think of…?)
Questions & Answers about ¿Qué te parece el plan?
Why does this use parece instead of a word like piensas (you think)?
Why is the verb parece in the "it" form instead of the "you" form?
What is the role of te in this sentence?
Te means "to you". It tells us who is receiving the impression. Because it is an object pronoun, it is placed immediately before the conjugated verb parece.
Since it translates to "How does the plan seem to you?", why use qué instead of cómo?
Even though "how" makes sense in the English literal translation, Spanish always uses qué (what) with parecer when asking for someone's opinion. Saying cómo in this exact phrase sounds unnatural in Spain.