Tapered sideburns are favored by the military and anyone who wants a tight, clean haircut. Cutting sideburns in this manner results in them fading gradually as they move down the face, as opposed to an abrupt cut-off. The technique can be done at home using a guarded razor and the correct tapering attachments.
Attach the left tapering attachment to the razor. Note that the longer end of the attachment must be the same length as the section of hair just above the ear, as it transitions into the sideburn. If necessary, use another guard above the ear to create this length.
Move the razor and attachment from the ear forward, moving horizontally across the sideburn.
Repeat the process with the right ear.