Painting figures may seem slow at first but it does speed up with practise. Several methods, including dry brushing, are used to help put an army together quicker.
Usually the figures are given a black undercoat first. Then the colours are dry brushed on. This is where paint is put on the paintbrush and then most of it is wiped off, leaving only a small amount on the brush. The brush is then lightly wiped across the high points. This leaves the black in the creases to give a great look of depth to the figure.
To enhance this further, often lighter and lighter shades are then dry brushed over the same colour, making sure that less and less pressure is applied to the brush so that the lighter shade does not fully cover the darker shade underneath. This gives good transition of the colours.
Some painters prefer a white undercoat if they want bright colours. The black undercoat looks like shadowing in the creases, but it can also darken the paint, unless several coats of paint are added on top.