Select a reference picture to use for your painting. Having a reference picture will give you a guide for choosing and blending colors, shaping the clouds and adding any desired details.
Squeeze the colors of paint you chose to use for the project onto a plate or palate.
Select the color that you wish to use for the sky's background. Use a wide-bristled brush to paint the entire canvas. If desired, you can combine two or more colors to create a colorful, sophisticated sky.
Rinse off your paintbrush using soap and warm water. Make sure to throughly remove all paint from the bristles.
Allow the paint on the canvas to dry completely before continuing.
Select a smaller, round paintbrush and load it with the color that you wish to use for the clouds. Do not dip your brush in water prior to loading the paint. Place the brush onto the surface of the canvas and paint a small circular shape in the center of the canvas.
Push the paint outward from the circle using a scrubbing motion. Don't apply any more paint to the paintbrush, you want to create a translucent rim around the cloud to create a wispy three-dimensional look.
Continue to scrub the brush outward until the paint is transparent. Create an uneven, puffy cloud shape by swirling your brush in a circular motion. Use your reference picture to guide you with creating a realistic cloud shape. Avoid making the cloud too round or too defined.
Repeat steps 3 through 7 to paint additional clouds. Try to avoid making the clouds uniform, use the reference picture as a guide. If desired, you can use different colors to add highlights or lowlights to the clouds.
Clean out all brushes using soap and warm water. Allow the painting to dry thoroughly before moving or transporting it.