Here are some tips on how to paint mass quantities of troops in a style similar to those pictured on this site.

Painting Tips - CS
Painting tips:

Mount about 10 figures at a 45 degree angle on hobby sticks using white glue

Prime half in Army Painter Leather Brown and some in Skeleton Bone or Rust Oleum Camo Tan . A few of the officers can be primed in Army Painter Uniform Grey. Paint in as much detail as you like, The rifles, faces, hands and buttons are fairly easy to pick out. Paint about 1/4 in captured Yankee paints. I use Anrea Blue from Vallejo for Yankee britches. When finished and light black wash will make the detail stand out.

Mix black, Burnt Umber and a little smoke (All Vallejo) with water until it is soupy and paint all the bases brown. Let dry, remove from sticks. I use flocking gel mixed with the same colors I paint the bases with a little more black as the gel is white. Before the the gel dries, sprinkle on some of your favorite static grass.