Making settings for stones is probably my most used (and favorite) technique in wax carving. With some practice, making bezel settings for gemstones can be quick and foolproof.

My biggest tips for making a bezel setting:
Make sure you are holding your tool perpendicular to your wax, or straight up at a 90 degree angle so you are carving the inside wall straight down.

Use baby powder on your stone so it doesn't stick when pushing it into your wax. You can also lay a piece of floss down first before trying to fit your stone in so you can easily pop it out.

Don't be afraid to start over. Wax moves quickly, so mistakes can happen fast. Just move on and try again, learning from your mistakes on the way.