When you decide you want to rhinestone an item whether it is a purse, shoes, belt, hat or clothing, you should first decide where you will be embellishing the item and come up with a general design or outline. The reason I suggest this is because if you are rhinestoning a hat, for example, you will likely be gluing rhinestones along the seams or the edge of the brim, etc. To have your finished project look sharp you must determine what the width is of the spots you will rhinestone, and choose the sizes accordingly. If you have a 1 mm seam and you use 1.5 mm stones they will overlap and look sloppy. Similarly, if you use a .75 mm stone in the same seam, they will be too small and the hat may end up looking like you had extra stones that you wanted to use up!