SEO? What?

Before I opened my Etsy shop I had no idea what SEO was. Now that I've been running the shop for over 2 years, I know that SEO means "search engine optimization" and that it could potentially help bring more people to your shop, but I'm still pretty useless when it comes to the intricacies of how SEO works. My mom has an Etsy shop as well (etsy.com/shop/zasuvintage) and is lucky enough to have a friend who is pretty savvy with computers. He figured out a way to improve her SEO by changing her listing titles and tags and her sales have improved dramatically! Seeing how it helped her, I'm now wondering how I can improve SEO for my own shop. There are tons of resources on Etsy with tips on now to do this, but I'm wondering what other shop owners have found in the confusing world of SEO. What have you done? Has it helped boost sales and/or listing views? I'd love to hear from you!