1. Profile picture
Wise people say that "Fine dress helps to impress," and this also applies to your profile picture. Choose a nice and appealing one that says something about either yourself or the things you sell.
2. Profile description
Your shop's profile should first of all include a few words about what you sell (e.g. handmade jewelry with gemstones; gently pre-loved vintage clothing; etc.) and a few words about shop policies (e.g. no returns; no trades; payments by PayPal; international shipping; etc.). People also tend to engage more with Instagram shops that are more personal, so consider writing few words about yourself and @mention your private Instagram account.