One thing this guy mentions that I hadn't previously thought about before invovled determining where the hole in the pan should be. Should it be in the front or the back of the pan? I never thought of this because my cats naturally face towards the front like I've seen all the other successfully trained cats do. But if you try and do this and your cat faces the tank instead, then his advice is really helpful!!
He basically talks about how the placement of the hole in the pan cannot only affect how quickly your cat catches on, but also where the cat will learn to naturally face AND this consideration could prevent splash-back!.
The blog has some pretty serious reproduction restrictions, so I'm not going to quote him here. But I do reccommend checking out his blog!