I know how to do kick flip quite good,
But I can not do at 100%
I can do about 5-6/10
How can I improve it?

By the way, sorry about the English ..

Just keep doing it, and try it onto stuff, like try kickflip onto ledges, and rails etc, that way when your just doing it on flat it seems alot easier?

keep trying dude, i used to be just like you but with practice and determination you can be perfect at them, well, almost perfect like landing them 9 out of 10 times dude

keep going on it

I'm practicing on it for several months, I'm stuck on this ..
Sometimes I try to do on rails and on boxes But that does not help me

Thanks a lot for the tips friends!

You need to mess around with different finger positions. Try moving your middle finger close to the bolts, and then try it right on the end of the tail. Try your index finger in the middle of the deck, and then right near the nose. Try every combination until you find the one that works best for you.

what helped me the most was staying fluid with my finger motions and not trying to snap flips ya know.

for me kickflips are the same position as a ollie just with this movement

start rolling, pop a ollie, same time while moving your front finger off the corner of the nose, and just follow through with that movement!, dont try to just snap the flip and hold back, hoping it goes where you want it to. follow through with your hand movements and just try to get fluid with them.

its alot of practice but once you know how to move your front finger and follow through it becomes automatic like ollies.

Just don't get stressed. i can never land tricks if im stressed, Have you watched weekfinger's how to kicklip video? thats how i learned!
BTW good english.

I had this problem too, you just gotta keep trying different finger positions till you get the right one then just keep practising over and over then when you get better try it over objects and it gets much easier.