l keep falling on the beginning part of the jump (thethree swings) and l can do a waltz jump really well.

Practice your foreward outside three turn and hold the ending with you leg extended behind you. After you are able to hold your check on the three turn you can start to worry about the jump. Holding your check is the hardest part of this jump. Also remember not to lift your hip. Keep them level while you are going foreward and backward. You should not be swinging around.