This week's tip:
I have just realized that nobody really discussed the proper way to sand the dot matrix of vehicles. What you need to purchase is 600 grit "WET/DRY" sand paper and wet sand the dot matrix area. Spray a little soap solution or water onto the dot matrix and make sure you use a rubber "Sanding Block". This way you will sand the dots evenly and decrease the chances of scratching the glass between the dots. If you are very careful, you don't have to tape off the clear glass but if you feel necessary, it is recommended to put some masking tape over the clear part of the glass so if you accidentally sand off the dot matrix, it won't scratch the glass.
I have tried 400 grit wet/dry sand paper and this can work but you have to be more careful as it can scratch the glass if you over sand the dot matrix. What you really want to do is to knock a little off the top of the dots so it reveals a slightly smoother surface so the tint can stick better to the dots. This also allows the adhesive to stick between the dots on the glass and eliminates most of the air pockets.
It is very important that you sand the dots evenly so you won't have one area flatter than the other, otherwise you will still see some uneveness where the film sticks on the glass and the area where it sticks only to the top of the dots.
Here is a picture of a Mustang that is done after wet sanding the dot matrix.
NOTE: I know alot of you use vinyl and I do sometimes too but for those people who sand the dot matrix, this information should provide useful.