Good task lighting is essential for art studios. I use task lights when I paint on rainy days or for evening work. Currently, I use Ottlite Slimline task lights. These lights are compact and adjustable, they fold for easy storage, they cast a pure white light on paintings, and they eliminate shadows so I can paint late into the night.
Watercolor boards are another handy tool to have on hand. I use a Guerilla Painter board to stretch watercolor paper and keep it flat while I paint. This prevents the paper from forming ripples when using painting techniques that require a lot of water.