Breakdown of Quels vêtements est-ce que tu veux essayer ?
tu
you (informal singular)
est-ce que
is it that / do / does (question marker)
quel
which / what (adjective)
vouloir
to want
Questions & Answers about Quels vêtements est-ce que tu veux essayer ?
Why is it quels with an "s" at the end instead of just quel?
How do you say "on" in "to try on"?
Why doesn't the verb essayer change to match tu?
When you have two verbs back-to-back to express a single idea, only the first one is conjugated (changed to match the subject). Here, the verb vouloir (to want) becomes tu veux. The second verb always stays in its basic, unchanged dictionary form (the infinitive), which is essayer here.
Is est-ce que required here, or could I ask this another way?
Est-ce que is a very standard and common way to form a question, but you have other options. You could use the more formal inversion (Quels vêtements veux-tu essayer ?) or the more casual everyday spoken structure (Tu veux essayer quels vêtements ?).