Really good job on launching your store. I think there isn't a ton to change, but I'm going to nitpick anyways, because there is always room for improvement :D.
After looking I couldn't find a sense of urgency. Imagine you are a customer browsing an online store. Maybe you are ready to buy maybe you aren't. But there is a good chance you aren't in the buying mood at the moment. If you add a sense of urgency to your store it can help more of your customers to buy, and have them buy faster. One way you can do so is by adding https://apps.shopify.com/better-countdown .
After looking I couldn't find reviews. Adding reviews would help your customers research the products they are going to buy. Plus if someone likes a product they bought from you they can leave a review.
After carefully reviewing I don't see a blog. A blog could be used to drive more traffic to your store, and you could also use it to recommend potential products that your customer could buy.
I wasn't able to find a FAQ section. Customers often times will want a lot of information before they make a decision to purchase. Adding an FAQ section with information about things like shipping rates, returns, and anything else relevant can help your customer more easily make a decision to purchase
You know your store is actually quite good, and I think with just a bit of love and care, you will be able to really succeed.
If this helped you consider signing up for my free email course at https://mailchi.mp/7d8692283c12/shopify-conversion-courseTo learn more visit https://www.answrly.com/
I just had look into your website.
You can add high quality image on banners and Description images of products.
You can use open new tab on the links on the footer section and items on grid page, then customers are spent more time on your store.
I suggest you can use regular Font Family(like https://juststag.com/pages/faq), I mean you can't use the bold font on website(not for headings), Which you have used that font not attracting.
I suggest you can add your website Facebook link under Facebook icon and Instagram link under Instagram icon.
Remember user may not scroll down the page to view your banner images. Not only at home page, It effects on cart page also check it. It's not good view of website.
I saw that the font size on the FAQ page was too big, i suggest to set them like the font size that you have used in the https://juststag.com/pages/shipping-policy page of your store. That one is easy on the eyes and more professional.
Your about us page is not really an about us page. The following Shopify article details the need of an about us page and how to write one - if you need guidance: https://www.shopify.com/blog/how-to-write-an-about-us-page
I know that this is how that particular theme was designed, but the product description could be changed to be located under the product's image instead of the side.
The homepage needs more work on the layout, and placement of the products. Also your instagram icon on the footer links to instagram.com but not Juststag's instagram.
Good luck with your store!