Recently I received a brief to paint for a client who loves very specific colours. I visited his home, taking note of the mood and colours thereof, but when I starting painting, I realised the overall feeling is going to be too 'cold' and decided to put down a wild, expressive, complementary colour layer down first. This held two benefits, firstly, it created a bold start which kept me from going realistic too quickly, and secondly, it created the potential for tiny patches of warm reds and pinks that could eventually shimmer through the cooler upper layers.
Deep red was chosen to complement the cool pastel greens. Complementary colours always make each other more vibrant. The drawing was done in a dark blue so that where the line work later shows through, it will be a colour that that looks beautiful and doesn't need to be covered up again.
The next step was to block in the back ground: strong reds can be very overwhelming and mess with ones ability to make good judgements, it needs to be controlled quickly! More colour layers were then worked into the face to build up richness which can later peak out from underneath.
The final artworks: cool blues and greens with patches of warmth showing through. Definitely a more vibrant outcome than if I had only used the colours the client intended.
I would like to encourage you to experiment with colour the next time you start a painting, purposely choose an under layer opposite in temperature and colour to the main 'final' colour. Be fearless, it is only paint and you can always cover it up again!