Mixing Gouache
"Gouache" sounds like a delicious French dessert. It's also a kind of paint, quite similar to watercolour but opaque if used thickly. I first learned about it from James Gurney's videos and have been wanting to get to know it better since. It mixes well with watercolour but feels quite differently; it's got that chalky look to it too that many people don't like and watercolour purists hate it, which, of course, makes it even more interesting!
As I wrote a while ago, I was thinking of using my computer to generate random colours that I would have to mix and get as close to as possible as a kind of exercise to familiarise myself with the properties of paint. I originally got this idea from Andrew Tischler's channel. Some time ago, I bought tubes of Alizarin Crimson, Cadmium Yellow Pale and Ultramarine together with some Titanium White to do this with. You can see the result above. I don't know if this exercise will be hugely beneficial in the long term since I can just go outside and match colours as I paint real things but right now, it feels good isolating just the mixing part. I don't yet have a good feel for how powerful each colour is and how much paint and water I need to nudge my mixture in the direction I want.
If you want to try this, I've found this website the easiest to use since I can press space repeatedly until I find a colour that interests me.