knees on elbows has to be "easy"..
get down on your knees
bend to put your hair line on the floor (not forehead, not head)
put your hands flat on the floor touching your head, with your elbows on the floor (to figure out where to put your hands)
where your elbows are, that's where you have to place your hands. put them there, keeping your head on the floor at your hairline
now without moving your toes from where they are straighten your legs. (this will raise your bum way up.)
make sure you are still on your hair line.
stop.. start over and over again until this becomes natural and too easy. you have to be able to do this without taking too long.. so that your neck doesn't get tired. keep your back straigt, almost arching.
then..
with you head on your hairline and legs extended.. bend ONE knee to put it on the elbow. you should be able to move that leg without moving anything else. (in other words.. your body has to already be in the right position with the weight on your hands and head, not on your feet)
bend second knee to put it on elbow.. your two feet can touch each other at this point to form a triangle.
good luck