Find scenes or parts of scenes that are each dominated by a single one of the primary or secondary colours. Make one exposure as the meter reading indicates, a second exposure half a stop brighter and a third exposure half a stop darker.
I have chosen to focus on the additive primary (RGB) and secondary (CMY) colours rather than the subtractive colours (RYB - OGV) because this is more relevant to me as a photographer.
This was taken earlier today outside Angus Steak House in Leicester Square. I took three bracketed shots which, from top to bottom are as follows: underexposed (half a stop), correctly exposed and overexposed (half a stop). There is a subtle difference between the first two, but I definitely prefer the underexposed image due to the increased contrast. The overexposed image looks flat.
This was taken this morning in the London Aquarium. I had to push the ISO up to 800 and use my 50mm lens wide open at f/1.4, as I was virtually in the dark, . The exposures are as per the red images, and I think the differences are more obvious here. Again, I much prefer the underexposed (top) image as the colours are more vibrant and there is a greater separation between the fish and the background.
Another shot from the London Aquarium. In this example, the underexposed (top) image is not only the most vibrant, but it also has the least amount of noise. Detail in the highlights was retained in the first two images, but the highlights were completely blown in the overexposed shot and it was riddled with noise.
What have I learned?
I normally use a polarizing filter to enhance colour, but I have one filter which only fits one lens. I can see significant improvement in the above images just by underexposing by half a stop. This is a technique that I can (and will) use from now. However, when shooting in RAW (not JPEG), most magazines advise that it's better to expose to the right. This apparently retains more detail and reduces the level of noise. However, all of the above were shot in RAW but I can see more noise in the overexposed images, so I'm a little confused to say the least! I need to to take another look at the histograms to see the reason for this.