The first thing we learnt was that the more dilute the watercolour, the less intense on paper. It all makes sense of course but there are 5 grades of consistency and ways of telling which by how runny they are on the palette.
We did still life as it's the easier subject. But here is the reminder of what I have been taught time and again, shadows look most vibrant when the complementary colour is used. Put purple with yellow, green with orange and blue with red.