This technique is particularly important for guys with faded hairstyles who want to avoid an abrupt contrast of bountiful beard and buzzed hair.
We asked Rob McMillen, head barber at Blind Barber in NYC, for his advice: "Start on your longest clipper setting and sweep outward away from the face to blend the beard with the haircut. Each guy can work his way down according to the length of the beard, but it is always safer to start with a long guard and slowly work your way down."
Basically, don't do anything you can't fix. Clean any strays with a longer setting, then decrease the setting two or three times to get a steady gradient. But be careful, because you need to achieve this graduated look within a 1-2 inch section of your sideburns.
One celebrity who does this best is basketball player James Harden, who appears to use only one or two additional clipper settings to achieve this look. Check out how clean the beard fades into the buzzed part of his hair, and notice where it subtly decreases in length: