Clouds are a great way to improve how you see artistically. Try a literal study (basic) or a memory study (advanced).
For more information on digital manipulation see the 'Digital U' series in the Learning Library.
Art Materials: See supply list for watercolor supplies. Main mixes shown here are Cobalt or Ultramarine Blue + Alizarin Crimson Permanent. Touches of Burnt Umber for clouds are mixed in and Cobalt Teal is used in the sky fade (near the horizon) - it's fine to use a tiny bit of 'warm' blue such as Cerulean, Peacock Blue/Pthlalo instead. Cobalt Violet is used at the base of the sky right near the horizon. Review the Watercolor Basics video in the Learning Library for and in-depth look at my supplies and colors if you are getting started in watercolor. R-3 (#10) Rosemary Pocket Sable brush shown with Stillman & Birn Alpha sketchbook.
After reviewing the Cloud Concepts video previously posted, think about what you'd like to do for a project. Pick a project to work on based on your own reference, or my video. It's important to know what your intent is when creating your study (digital or with sketch media). Ask yourself what do you want to really say about the clouds. Try several ideas out.
Play with your studies to see what feels good. You can also do this exercise with a pencil and paper for shape, but it's good to try the sky fade idea and some of the peach cloud colors next. For more intermediate or advanced artists, challenge yourself to start doing memory studies of clouds. You will be surprised at what you learn and this will deepen how you look again at the sky.
You can use any media for your small studies.