How can you make your cuts as precise as possible when hand-cutting?

Answer 1: One option is to use vinyl tape as a guide when cutting to make sure your lines are extremely straight. 

Answer 2: Get an extremely bright LED light and place it in the rear deck when cutting the rear window and windshields. Often, tinters make mistakes because they cannot really see what they’re doing. Adequate lighting makes all the difference when it comes to precision cuts.