If the board if getting away from you its usually one of three things. Your kicking too hard off the kick. Try to imagine kicking up and out rather than straight. The perfect flip comes from your foot sliding across your board not actually kicking it. Your bodyweight is leaning in the wrong direction. Focus on keeping your weight balanced over the board and your shoudlers should be lined up with the deck aswell. If this doesnt help keep at it. Means you just need practice

Jump where you expect your board to land. When learning kickflips and heelflips, the board will go in the direction that you flick it until you gain better control. Anticipate where it's going to be and land on that wood like a fly on a pile of crap.

Try putting your foot higher on the board and flicking straight out

Just commit

I’m guessing you’re landing with your front foot? If so. Focus on getting that back foot up high under your ass, when the board is completed spinning both feet straight down over the hardware