I recommend choosing comfortable clothing that makes you feel good in your skin. Try not to choose an aspirational outfit that you would like to feel good in, but perhaps actually don’t. Beyond that, it only depends on the formality of your session. If you’re looking for more or less formality, think about how you might dress for a comparable event — church picnic, family reunion, a cousin’s wedding, an afternoon at the boardwalk. Dress for that situation. If you want to create portraits for a dating profile, you will want dress like the best version of yourself on a normal day, not necessarily your “Sunday best”.