Getting more comfortable with my gouache set

I have been trying to paint more with gouache and watercolor these past few months. At first to get rid of my gouache paints sitting around for 5 years, but now I've had time to get more comfortable with thinning out my gouache to act like watercolor. It's a little more time consuming since I had to trial-and-error most of the way since there aren't many tutorials on how to paint this way. I'm still on the fence in purchasing opaque gouache or transparent tube watercolors when I run out of certain colors but a few more doodles should give me the answer I'm searching for. In the mean time, here are some studies done from some of my favorite artists.

Sketches at Workshop