These three worksheets are included in my book, but are also available here separately.  The first one lets students sort nouns into columns based on whether they are common or proper.  The second one has students find and correct proper nouns that have been written with a lowercase letter as they rewrite the senteces.  The third one lets students replace the common noun in each sentence with a proper noun of their choice, giving a name to the common noun.  For example, "dog" can be replaced with "Bruno".   Makes a great assessment tool, in-class practice, homework assignment, or review activity!