Dallas here, from the Social Care Team here at Shopify. This is a great question and I would love to be able to help you out!
All the products that are shown on your home page should benefit your Unique Selling Point (USP). This USP is what makes you stand out from other vendors or stores. Even if your products aren't overly distinct you will at least want to showcase the items that will captivate your potential buyers to bring them deeper into your store.
Just note that having your main images and putting time and effort into your homepage doesn't mean that your other pages aren't as important. If you want you can even look at other pages as a 'Homepage' since some customers won't always land on the main page first. On 'Collection' and 'Product' pages make sure to insert captivating descriptions and keyword rich text. This will help to not only grab more of your customers interest, but it will also help you make your pages rank higher on google as well.
So with all of this being said, you will want to put the products on your homepage that you think will be the best to keep customers interested in your store. Those may be the best sellers, however, they also may not be. The best way to find out what products are being clicked on the most would be to use your analytics tool of choice to see what pages are being visited most frequently. This data may vary from the products that you sell the most of, so just make sure that the first priority is to capture their time and attention to keep them on your store.
I hope this helps. If you have any other questions do let us know. Our support is here to help.