Pjz99's link to PhilC is an excellent way to learn the difference between dynamic and conforming clothing.  And IsaoShi's advice couldn't be truer.  But be aware that conforming clothing does have it's drawbacks with certain poses and pokethroughs.  Don't get us started with supermorph figures and clothes that don't fit.  That's another can or worms altogether.  Find some conforming clothing to play with and gradually work your way to dynamic.  Decide which method is right for you.