Some of the outfits (like Tara Palmer-Tompkinson's all ultramarine outfit) were over the top with their color blocking, really a nude shoe and a matte gold clutch wouldn't have gone astray in this look.
The art of color blocking with different colours is to either choose a color and a complimentary neutral, or to choose two colours of similar strength (intensity/saturation of the colour) and undertone (warmth or coolness).
colour blocking by imogenl featuring a knit cardigan
For inspiration check out Angie's color blocking look.
Sal at Already Pretty also does lots of color blocking in her own outfits - here you can see a variety of color blocked outfits, plus some tips on wearing silk scarves!