Folding bookshelves are a great way to add height quickly. They bring everything up to eye-level which is so important for displaying your items.
I love these bowls for displaying your smaller upsell items. I have lip balm, face masks, and travel-sized towner in bowls just like these right next to my checkout area.
Getting your jewelry up where it catches the eye is extremely helpful for handmade artists. Make sure the stands match your branding so it doesn't feel out of place with your carefully crafted jewels.