This article is from the Miniatures Painting FAQ, by Brenda Klein email@example.com with numerous contributions by others.
Drybrushing is the best method of highlighting any large area or
area with repetetive detail, such as armour. For faces, hands,
buckles and the like, highlighting can be achieved by taking a
slightly lighter shade of the base (mixed with white or a lighter
tone) and going along the raised areas lightly. A fine brushpoint
is required, as is a steady hand. For faces highlight the chin,
nose, and cheeks. For hands go along the backs and each finger.
For other detail, pick the spots that should show up best and
give them the lightest highlights. It's common to highlight
twice, each time getting lighter in tone and finer in line.
A bit of blending is required to keep things looking natural, but
this blending is easier than the large-surface technique. Simply
keep a damp brush handy and brush very lightly toward the darker
Again, this technique takes practice, but is worth the effort when
the miniature is completed.