In my experience, to create best results, use the best materials available. Here are my recommendations:
PAPER - Arches 300 lb. Hot Press Watercolour Paper
PAINT - Either Windsor & Newton or Grumbacher water colour paints. I use: Burnt Sienna, Payne's Grey, Prussian Blue, Yellow Ochre, Lemon Yellow, and Crimson Red. I find that most colours can be created by mixing combination of these six, but there is a huge selection available.
BRUSHES - Either Windsor & Newton or Grumbacher: one #3 Rigger brush, two x 1 inch flat brushes, one 1.5 inch flat brush and one 3 inch flat brush (this can be a house paint brush).
SPATULLA - Round Tipped 1010
MASKING - Liquid Latex Frisket (Miskit), half inch, three quarter inch, & one inch masking tape.