I first learned misty's earlier this season, and they are much easier than they are made out to be.  First of all, it is much easier to do one off a bigger jump than a small one.  Make sure you have a soft landing on the jump also in case you fall.  As for actually doing it, when you throw it, make sure you aren't throwing really hard down towards your ankles because that will cause you to more of an off-axis frontflip with a twist at the end. Making sure you pop off the jump is important as well.  When I did it, it was just kind of a feel thing.  When my body felt like I had come around, I started looking for the landing and because I had gone off a bigger jump, I had a little bit to find it and stick it.  Just go out, think about yourself doing it then do it.  If you just throw it and have a friend watching, they can tell you what looked wrong so you can fix it.  And last but most importantly, make sure you have acutally committed to the trick before you went off.  There were a group of guys learning them with me, and just about everyone else took at least one or two runs where they went up then pussied out.  It's much better to fall trying than to have never tried at all.