Chinese characters decomposition is a very effective way for learning and memorizing Chinese characters. It is based on the knowledge of 214 Chinese radicals.
Decomposition of the Chinese character 云 yún ‘cloud’:
云 yún cloud
二 èr two
厶 sī private
Synonyms: Structural analysis of the Chinese characters, Breakdown of the Chinese characters.
More information and guidelines on decomposition you can find in The Chinese Character Decomposition Guidance