In my experience, lateral raises are one of the harder movements for guys to do properly and to get a proper "feel" out of. Just not easy. When it comes to rear delts one of my favorite movements is to do them face down on a 35 degree bench. None of the bending over, uncomfortable crap. This way rocks, imho. Remember, the rear delt is a small muscle so form / execution is crucial to development. Meaning focus on the movement and don't swing the weight through it.