When creating clouds in watercolor painting, one does not use white paint. You need to save the white of the paper to create white clouds. As you paint your sky wet into wet, leave spaces for the white puffy clouds. Often times, the white of the paper shrinks as the sky color bleeds into the vacant white but wet area. To remedy this situation, use a tissue. A plain old ordinary blow your nose type of tissue.
1. While the paint and paper is still wet, blot your clouds with a clean tissue. The color will be picked up from the paper and absorbed into the tissue.
2. Remember to twist and turn your tissue each time you blot. You want to blot with a clean portion of the tissue each time.
Keep the blotting to a minimum. Do not create a line of exact same sized, repetitively stamped clouds. Create clouds of varying sizes and shapes.