 <p>I usually select a base color and change the hue in 5-6 step (=changing main color) If I need more colors, I'd change saturation (strength or grayish) or luminosity.</p> <p>The problem here is that you should avoid two adjacent colors (on your drawing) to be close together in terms of 'distance' of the three values H,S,L.</p> <p>This is quite easy to implement and gives acceptable results.</p> <p>e.g. (use the windows color editor)<br> (S=140, L=160): H=0,40,80,120,160,200<br> (S=90 , L=180); H=20,60,100,140, 180</p> <p>Please don't use too many colors. Play with fill patterns as well.</p>