Look up darning if you’re not sure how to start, it’s an easy way to get started or at least it was for me!! I don’t know about you but the clothes I get holes in most often are socks, and more recently, a few sweaters my cat decided to eat golf ball sized holes out of. I still haven’t got the right yarn to fix the sweaters, but the socks are good as new. I kind of get excited when one of my garments gets ripped if it’s in a place where mending it visibly would work instead of just sewing the seam back shut.