If you have recently lost weight or the ring that you own has never fit you correctly, consider how to resize it so it fits you properly. While a ring that is too small requires a jeweler's intervention to enlarge it without damaging it, a ring that is too large can be fixed at home. A loose ring is one that can easily become lost, so choose the ring resizing option that best fits your situation.
Install a metal ring guard in a metal tone that matches that of your ring. A ring guard is a small saddle that sits on the bottom of the band, closest to your palm, and it helps the ring fit more snugly on your hand. A metal guard is sturdy and unobtrusive when installed.
Put on a plastic ring guard on your ring if you are planning to get the ring resized soon. A plastic ring guard is less sturdy than a metal ring guard, but is cheaper.
Tie a long strand of thread around the back of your ring's band and wrap it around the band until the band is thick enough to stay on your finger. Secure the loose end of the thread with a small dab of glue. While this method of ring resizing tends to come loose after enough abrasion, it is a good stopgap measure if you do not have the time to buy a ring guard.