If your wife/girlfriend/mother won't be seen in public with you in clothes
you picked out yourself...well, this page is for you. A basic understanding of
color theory is a great asset to your painting. A good comprehensive site is here. It has color wheels
and palettes, explains why there are no true primary colors (in contradiction to
what the third grade art teacher told us), and has some interesting information
on the history of color theory. But...
I've done some work for you already.
Two-Color Complements, Basic
These colors fall opposite each other on a color wheel and strongly contrast
each other. Rough GW color equivalents would be: Red Gore/Snot Green, Enchanted
Blue/Blazing Orange, Bad Moon Yellow/Liche Purple.
If your army is painted in green and white, then reddish details would really
stand out. Gold trim on a purple robe will jump out more than silver.

Two-Color Complements, Muted
These are darker, grayer, less saturated variants. Closest GW equivalents:
Scab Red/Dark Angels Green, Storm Blue/Bubonic Brown, Scorpion Green/Warlock
Purple.
If your Wood Elves are painted in dark green and blues, you could use a
russet brown for leather details instead of black, or dark red gems.

Two-Color Complements, Pastel
These are produced by adding white. Paint your army pink or lavendar at your
own risk.

Three-Color Complements, Basic
These are colors spaced evenly (well, sort of) around the color wheel. Red,
yellow, and blue are primaries, orange, green and violet are secondaries. I've
included a sample highlight color on each swatch.
A tri-color palette is recommended for most miniatures.

Three-Color Complements, Muted
These are schemes I work with frequently. They provide a nice balance that
lets details stand out without making the figure appear garish. A fighter in
dark blue garments might have gold or bronze weapons with red details.

Three-Color Complements, Pastel
Easter! Jellybeans! Sweetness and light!

You don't really want to know about tertiary complements, do you? Well,
you'll just have to wait. I'll be adding material on how to deal with browns,
grays, and those tricky skin colors.