The digital art package that I use most is Corel Painter 12, (thought I often import work which started on the iPad).
I find that one of the challenges of Corel Painter is finding the right brush to create the effect I'm after. Particularly with watercolours, as are three sets of watercolour brushes: "Real Watercolour", "Watercolour", and "Digital Watercolour". To help find the right watercolour brush I eventually took to writing the name of each of the brushes, in that brush. It took longer than I expected! So I'm posting them here so you don't have to do the same.