Unless you're actively going for that caveman look, it's a good idea to keep your beard in good trim. Otherwise, good luck finding a decent loincloth and club these days. . .
Step 1: Dry beard Make sure your beard is dry. Wet hair is more relaxed and therefore longer, so trimming it wet will leave you with a shorter beard than you expected once it dries.
Step 2: Comb down through beard Comb down through your beard several times, in the same direction your facial hair grows, to get all the hair facing in one direction.
Step 3: Comb up through beard Now comb up through your beard, against the direction your facial hair grows, to fluff up your beard as much as possible.
Step 4: Begin trimming Concentrating on just one side of your face at a time, begin trimming. Do this by angling the comb slightly outward from your face and clipping any hair that sticks up beyond the outside surface of the comb. Work from your ear down toward your chin.
TIP: If you are using a beard trimmer, you don't need the comb—just set the trimmer's guard attachment to cut the least amount of hair possible, then decrease the setting to remove more hair with each pass as desired.
Step 5: Repeat process Repeat the trimming process on the other side of your face until the two sides match.
Step 6: Trim outline Define your beard edges and neckline by trimming the outline of your beard into clean, even lines and removing any stray neck hairs outside your beard shape.
TIP: Wetting a razor and shaving along the edges and neckline of your beard will give you a sharper outline than scissors.
Step 7: Comb through & touch up Comb down through your beard once more, touch up any spots that require it, and get on with your day.
FACT: Even cavemen trimmed theirs beards—so as not to give their enemies a handhold during combat.