User:Juiced lemon/Common mistakes
Publicity: user's pages (or similar ones) must not be categorized in the topics structure.
Structure duplication: When there are a gallery and a category about the same subject, the gallery is usually categorized in the matching category page, which is taken to be correctly categorized according to customary rules (in particular, regardless of its content).
Overcategorization: Media files, galleries and categories would be categorized using a minimal set of categories covering the different features of the file, or the different aspects of the subject. Extra categories must be removed, unless they comply to a particular scheme.