Well, if you don't have a real bunker to practice out of, then beach sand
might help...of course you won't get an idea of spin or rollout but you can learn a few things. One thing is that the amount of moisture in the sand and how packed it is makes a difference. Try to find a place on the beach that has sand approximately the same consistency as what you would find in a bunker. Normal sand shots require a much steeper delivery than a regular pitch shot...take the clubhead up quick and bring it back down steep and follow through...let me repeat that...follow through. Fairway bunker shots are different, however. Try hitting 4-irons out of different consistencies of sand...you'll find that in loose, dry sand if you let the clubhead take a very big bite then it kills your shot...you really have to catch the ball clean with very little divot so the clubhead doesn't hang up...and always follow through. Acceleration and follow-through are crucial. Hope this helps, good luck.

Shade