I'm pretty sure everyone develops their own personal style but many of the key elements are similar. I use one edge of masking tape as my guideline and use a cut off wheel - in either a Dremel (a little slower) or in a die grinder (faster). I prefer moving the cutting disc so that the disc rotation is against the direction of the cut. That puts dust in front of the movement and has to be removed when it builds to the point of covering the cut line - but the wheel doesn't want to pull itself into a place you don't want. Some folks cut the other direction because the cut line stays visible but that tends to build a bridge of solidifying material across the cut behind the wheel and has to be removed before the next pass. Which ever way you prefer, the key is to not cut too deep in any one pass; take your time. Once about 3 passes are complete you'll have a grove that makes it easier to follow the line. That's when I naturally start to go faster and forget the rules - with predictable results. Eddie points out something key - because the hinge will cover the main part of the longest cut, start there. If I am remembering correctly, doesn't the cut for the hinge have to be fairly wide - which means two cuts and lots of practice? (Double check, I may be thinking of another part.) And, if you are going with the flap drive rod hole option (rather then the slot), I'd recommend cutting or drilling the hole before making the cuts in the sides.