With my French I paint pretty simply.
I take the largest single area of colour (WHITE!) and do the whole figure over in a slightly darker version of it. This involves adding about 5% of a pale brown to my white and just making sure the whole figure is thoroughly covered.
Once dry, I lightly load a brush with pure white and brush roughly down the whole length of the figure working from top to bottom. This has the effect of putting the lightest "colour" on top of the figure while leaving the recessed areas darker.
Now I do all the other bits of colour - facings, flesh, hats, hair, belts, boots, buckles and braces.
Flesh areas get a thin wash of brown ink followed by a highlighting of a paler shade of flesh.
Hair, which has been painted over in black gets touched in with white to represent powdered locks. The lower lip might get a tiny dash of red ink. The occasional moustache might get a couple of dashes of white over the black base to denote a veteran.
All other colours are left unhighlighted.
Lastly, I slightly thin some white to a milky consistency and use it to paint areas like the tops of shoulders to finish the highlighting. This is also a good opportunity to cover up the inevitable mistakes I make when applying all the other colours.
For a figure with a different main colour (say the Gardes Suisses with their red coats), I do a base coat in the main colour, wash that over with my sepia brown ink. Wait for a few hours while that dries and then heavily "wet'brush" it with the main colour again to restore the brightness.
This is how the Gardes Suisses test figures further down this page were painted.