There is much science and theory on choosing a palette, for example a primary palette, tertiary triad, split complementary or harmonious triad - the list goes on! Proprietary Colour Wheels are great BUT they're not based on watercolour pigments/colours we can buy, they're printed using four (or 6) colour process based on commercial primary printing colours cyan, magenta, yellow and black. In addition, a true colour wheel is made up of primary colours that are neither warm nor cool but neutral.
I have to admit I don't have a secret palette selecting trick, my palette is based on the pigments rather than "colours". Hence, I'm more interested in what my pigments will do together, how they mix together (can i make a great, interesting dark), how they react to water, paper and each other. See my youtube video below.
For example I could go and buy lemon yellow and Paynes grey. Unfortunately for lemon yellow and Paynes grey, they are 2 pigments I like least, lemon yellow is too cold and too opaque, not a good mixer, and Paynes grey dries about 50% lighter than one expects - too unpredictable for me!
My faves for a long time have been transparent watercolour pigments and then I throw in some goodies at the end.
So when you ask me "what colours?", my first answer will be "what have you got and what can you do with them?" I often select 3 primaries, or a version of 3 primaries and make a colour wheel, it doesn't matter which 3 colours/pigments, all one needs is a version of a red, blue and yellow. It could be burnt sienna for the yellow, prussian blue and quinacridone magenta, the point is what new colour combinations will you be able to create?
Another question for the painter to pose is what kind of mood or story do you want to tell? For example, a dark winter's day or a happy summer day?
For the non-realist painter "What colour do i feel like painting today? do i want a pink painting or a blue painting?" the answers spin off from there, if a pink painting one could either choose a complementary green or harmonious colours red orange yellow and then an accent of purple or green.
What colours do you like? Head down to your local art gallery and spend a few minutes actively searching for colour combinations, whether you like the painting or not, is a good exercise in palette selection and most importantly, discovering your own likes and dislikes.
let me know how you get on - leave a comment!! :)