If you have a wall with a mat on it, you can do a press with your head near/against the wall. As you press, it will give you guidance as to where your hips/feet are in relation to your head.
When you can do a press satisfactorily, and you feel you can do it without the guidance, move slightly away from the wall and try. If you get up without touching the wall, then do the last step and make it really tough on yourself..
Turn around and stand in a straddle against the wall, or sit in a straddle if youre really strong. Press up, and dont let your feet hit the wall. This will re-enforce the crunch up position for an appropriate press.
If at any point, the press becomes difficult and you wish simply to work on the finishing phase, you can always take a pannel mat and use as many panels as you need to stand on (hands on the floor). This will elevate your hips and make the press easier to rise.
After you get your press, to best way to keep it is to press down. Learn how to press up from a straddle sit on floor, hit the hand stand, then press back down to a straddle sit. When you get stronger, you can do it without sitting on the floor.
When you get really strong, you can do it from a V-Sit.
Good luck!!!
Ryan