as well trial and error. There are many online sources on tips and tricks but all very basic, just remember you can always take more off. I started with the 36 grit then moved to the 50 followed by the green and yellow disk. buy this point it will look smooth, but will not be untill you use a sanding block. than use an angle die grinder to get all the tight areas as well the sides. Then the long hours of hand work. hope this helps.