I may not have this quite right, but here are a few things I think have reduced my spin outs (which a year or so back were pretty frequent

):
The main point that really makes a difference is if you are spinning out a lot check your harness lines aren't too far forward. Extra load on the back hand causes a natural increase in pressure on the back foot. I think this is also a symptom on those days where you just can't pull it back in after spinning out.
If powering upwind, either pick a path around the bigger chop as if you spin out you loose all the gains made up wind in a few seconds of sliding. For medium bits of chop, take weight off your feet, put all your weight on the boom and bend the knees as you go over to keep from jumping, then power up again.
Also, spend some time in flat water and small chop deliberately loading up the fin and trying to spin out. After a while you can feel the early slippage and react quickly enough so you don't loose it.
Hope that helps.