Sideburns are important men's style features, defining the hairstyle and framing the face. Although you could simply trim your sideburns with a guarded razor, you have more control over the precise length using scissors and a fine-tooth comb. Getting the exact length you want might take a little practice, but before long you'll be trimming your growth like a pro.
Comb your sideburns downward. This is the natural direction of growth. Remember to comb them when dry or minimally damp, so you don't end up with thinner sideburns than you anticipate.
Slip the teeth of the comb up and under the hair. A small amount of sideburn hair should protrude a little from above the teeth.
Fine-tune the depth of the comb, so it leaves the amount of hair you want to trim exposed on top.
Snip away the excess growth you see protruding from between the comb's teeth. Keep the comb as straight as possible, so the growth protruding through the teeth remains even all the way across.
Cut away any excess hair encroaching on your ear with the tips of the scissors.
Shave the sideburns' length based on personal preference, using your disposable, straight or electric razor. You can keep the length conservative -- stopping roughly in line with your ears' cartilage or above -- or longer for a more dramatic styling effect.
It's normally a good idea to check growth and thin sideburns every three days or so.