Maybe try using your arms to stabilize, I don’t look anywhere particularly

Try focusing on a point in the horizon. Pull your legs up a bit in the air. Keep your eues level duting the whole rotation. Try off a sidehit or a small jump

The key is to put lots of pressure forward into your shins. You have to exaggerate this when you are starting them. Focus on getting a good pop and leaning forward and try to keep your arm rotation level

Keep your legs shoulder with apart lift your head up a bit don't look down at all. All of your spin should be from your arms if u feel u need more or aren't confident about it look the direction your spinning don't look down until u want to land

If you’re not already doing it, look over your shoulder. If that doesn’t work then, I know this may sound a bit dangerous, but if the takeoff isn’t the problem, try doing your 360s on bigger jump. You’ll have more time to spot your landing and you won’t be spinning as fast so knowing when to stop will be easier. Last thing, try to practice your 360s on trampoline or on flat ground it will help with your air awareness so knowing if you span enough won’t be a problem.

Try to search Landing with your eyes, so your head and your shoulders are spinning together. And finally if head and shoulders spin pretty fast, all your body may keep spin automatically