Light - Bright - or White

To get white brighter you need to have the darker tones. Dark against light make one or the other stronger. Now by knowing that you can lead your viewer to what it is you want them to see.

Monet and the impressionist used the light and dark trick to light the world. Also they allowed the painting to come together in our eyes or mind.

By knowing and planning out just a little bit of your painting ahead of time you can point out the way we see your painting.

Something I don't say much about is the way your brush strokes end up on the canvas when hung in a home or gallery. If your  brush strokes are not horizontal the light on the sky or subject may be unsettling.

Keep your brushes wet and stay bright.