Try experimenting with paper types
I like painting on many different types of paper. It really pushed me to control gouache as a medium when I first started using it. The thin moleskine sketchbook paper forces you to apply the paint rather thick and dry, while Canson art board has an absorbent surface and enables you to layer the paint. Toothy watercolour paper suits a dry brush technique, which creates interesting textures. You can learn all types of gouache application just by painting on different paper surfaces.