Vibrant watercolour - how can you make your watercolour sketches and paintings more vibrant?

Vibrant watercolour

How can you make watercolour sketches and paintings more vibrant? Careful colour mixing is one way and, of course, this goes for all types of painting. If you mix more than 2 colours together then there's a chance that your colours will become duller or even muddy looking. This can be made worse if you are using student quality paint which has less pigment and more filler.

Transparency
I've recently been checking the transparency of each colour I use.   (I have a mixture of Schmincke and Winsor and Newton artist quality watercolours.) Currently, I'm experimenting, particularly with flower sketches, using all transparent colours and, not surprisingly, there's quite a difference in vibrancy. There are a number of reds, blues, yellows etc to choose between and I've removed the opaque ones and put them to one side for now.

You can check paint transparency before you buy a half pan or tube by checking the maker's info. A small square symbol that is completely black indicates that the paint is totally opaque. Totally clear means it's transparent, an so on...