Wrap the belt around your waist. It should sit about at your waistline. Attach it at the back by sliding the hooks into the clasps. Choose the line of clasps that is the most comfortable for you. This step is basically like attaching a bra. If you have trouble attaching it in the back, hook it together in the front, and then move it around to the back.
You’ll want your straps to be at slightly different lengths. The ones in the back should be the longest, giving you room to bend over. The straps on the sides should be an inch shorter, and the ones on the front should be two inches shorter than the back, all of which will help you bend easier. It also helps when you sit down.
When you fasten a clasp, push the rubber nub from behind so that you can see it sticking out through the front. However, don’t push so hard that you tear a hole in your stockings. The top of each clasp has a wide end and a narrow end at the bottom. Start with the wide end, sliding it over the nub, then pull up so the narrow end is surrounding the nub, holding it in place. Be careful if you have plastic clasps. If you apply too much pressure to a plastic clasp, it will snap in two, and your garter won’t be usable.
Make sure you sit down and stand up with the garter belt on so you can see how it fits. You don’t want it to have too much tension when you sit down because it might pop off. However, when you stand up, your thigh highs should be mostly taut, as you don’t want them pooling at your ankles. Loosen and tighten the straps as needed.
Therefore, if you’re only going to wear the garter belt for a little while, it’s fine to put your underwear on first. However, if you plan to wear it all day, you might want put your underwear on last, though under your skirt or pants, of course. You can also go without underwear if you prefer.
You want a garter belt that stays in place. If it slips, your thigh highs will slip also. However, you don’t want one so tight you can’t breathe. Make sure it’s loose enough to be comfortable. Finally, look for one that is adjustable. Most of them will have several rows of hooks, much like a bra, so that you can make adjustments as needed. [5] X Research source
You can even find garter belts with many more straps, up to 8 or 10, which will hold even better. Also, thick straps are better because they’re less likely twist and they provide a better hold.