Where are you doing them? Kickers, cat tracks, side hits? Personally I found cat tracks the easiest to practice from as you don't have to worry about absorbing the lip of anything, you can just set up the heelside carve and counter rotation, pop from both feet evenly, have the snow drop away under you, and rotate it around.

For running out of twist, the only 2 options I can think of is just throw your shoulders into the twist more, or carve a bit harder during your set up.

 

keep looking over your lead shoulder in the direction you're spinning. so if you're regular, keep looking over your left shoulder until you're just about to land. you won't need to do in the long term but this habit will keep your shoulders leading your rotation until you're used to getting enough air to slow your rotation down.

it also helps to pop a little with both feet on whatever you're hopping off of. you just want a small pop which allows you to suck up your knees a little which in turn keeps your body more compact and balanced.

side hits leading onto a cat track or wedge-type hits like the corner of a tranny/hip are also good because it allows you to get more air without committing a ton of speed.

and i don't know if this is necessarily an issue for you but counter rotated 180s don't require a setup carve. if you're trying 360s off of a kicker, having a setup carve really helps getting 3s down because you'll carry more speed and momentum into the lip of the jump. this also gets you into the habit of staying on edge while taking off which feels a lot better than catching an edge on a lip (this is the suckiest of all things that suck)

(img is from snomie)

 

Grabbing indy (rear hand on the toeside between the boots) also helps keep your shoulders in the right rotation.

For me, the most comfortable frontsides are the ones where i dont actually think about the spin once i have started. If i do the set up carve and preloading/pop correctly, in the air i dont even try to 'spin'. The spinning momentum has already been created and i just have to float it through. As a result my upper body stays much more smooth, and most of the time it will come out a smooth spin.

 

line your shoulders up parralell with the snowboard, right before you take off. tense your abs up, and keep looking over your shoulder across your shoulder, not down.

bringing your knees up as tight as you can to your body, will allow you to drop the board that extra 90 as well! Give it a shotshotshot