Let me give you a bit of background. Outside of Star Wars I participate in various reenactment type groups based on the Viking age. Most involve combat, from full contact boffer sports to choreographed and free form live steel combat. It becomes very inconvenient for your wraps to come undone while participating in these events. Because of this, I have learned a few things about doing leg wraps (winingas to us) in an effective manner.
This is not the only way, and it may not be necessary for you. Everyone is just a little bit different, so you may have to alter what I'm showing you to work on your legs. The goal is to wrap you legs tightly while conforming to the natural curves of your calves. Gaps should be non existent.
I make my wraps around 4" wide and 12' long. This gives me more than enough material to wrap from ankle to knee. You may find that you don't need them as long, and that's fine, just don't short yourself. Start out long and shorten it to your preference. Use a medium weight material, preferably with a rough texture. This will help keep them from slipping down your leg. A slight stretch in the material is fine, but towo stretchy and they may come undone.
To start, roll your wraps up into a cylinder. Do this when you first make them, and every time you take them off, and it'll be easy and quick to wrap your legs.
Starting on one side of your leg, begin your wraps.

Wrap up your leg until you reach the bulge of your calf muscles. You want to wrap as tight as you can without cutting off circulation. This will help keep the wraps up while you troop. Loose wraps will come undone and you'll have to stop and redo them.

Take your wraps wide, going up over the top of your calf muscle near the crook of your knee.

From there, wrap wide back to the bottom of your calf, making an X with the wraps.

Repeat the previous two steps until you cover any gaps in the wraps.

Take your wrap wide to the middle of your calf muscle, then spiral your wraps up to the crook of your knee. Tuck a couple inches of the excess into the top layers to keep it from coming unraveled.

Repeat on other leg.
Things to note. It took me 2 years of fighting to figure out how to get my leg wraps to stay up. You may not get it right your first few times, but don't lose heart. Most people I know don't wrap tightly enough or high enough at first. If you don't at least go past the thickest part of your leg, the likely hood of the wraps coming undone is increased. Since I started wrapping my legs in this manner, I haven't had to stop during combat to fix my wraps, which effectively takes me out of the game for a few minutes.
If you have any questions, feel free to to ask.