If you want to improve your watercolor painting skills, then preserving white is the most important skill to master
WAYS TO PAINT WHITE IN WATERCOLOR — Pam Ash Designs
Preserving White in Watercolour (7 Reasons You DON'T Need Masking Fluid) — Kerrie Woodhouse
Watercolor and Preserving White, Guardian
WATERCOLOR TECHNIQUES
Tutorial- How to Varnish a Watercolour Painting and Mount on a Wood Panel — Andrea England Fine Art
WAYS TO PAINT WHITE IN WATERCOLOR — Pam Ash Designs
Paint Watercolor Flowers With Light and Depth: A Demo
18 essential watercolour techniques for every artist
David Bellamy – Reserving whites in a watercolour