Mono-coat Trimming
One trick that helps me is masking tape. I apply masking tape to the model around the edges i need to cut before applying covering. Then when it is ironed down except for about 1/4 to 1/2 inch at the edge i cut it with a straight edge and a single edge razor blade over the tape. I find that you can press a little harder and not have to worry so much because of the tape underneath, therefore getting a better edge with less chance of snags or cutting the model. Then just pull the masking tape off and finish ironing down the edge. Its also good for trimming. You just put the masking tape down where you want the trim to end, then using a sharpie and a str8 edgemark the exact line you want on the masking tape. then, iron down your trim up to the tape, and use a str8 edge to cut the trim at the sharpie mark (you can see it through the monokote), pull the tape off and finish ironing down. It works for me anyway.