Just as the word "I" should be capitalized, your students need to understand that contractions containing it must also be capitalized. Give them a list of contractions and see if they can pinpoint which ones need capitalization. You could also put them into sample sentences and have the students correct each one to understand how this rule relates to sentences. An example could be "If I got a new puppy, i'd name him Rocky. I think he'd like that name."
Once they understand that a noun describes a person, place or thing, teach them the distinction between common nouns and proper nouns. Give them a series of pictures or brochures and have them create captions for each photo, properly capitalizing any place names or specific people in the captions. When they finish, proofread their work with them and have them share their captions with the rest of the class. Another activity includes writing a list of common nouns and having the students come up with proper nouns based on the common ones. For example, if you list "writer," "singer," and "your home state," they could write her favorite author, musician and the state you live in.
Hand the students a list of books, movies, songs and TV shows and have them capitalize them appropriately. While this may first seem simple, they will have to understand that not all words in a title automatically get capitalized. Explain that unimportant or common words like "the," "and" or "for" don't require capitalization unless they are the first word of the title. A good example is "The Grapes of Wrath," where "the" is capitalized, but "of" is not. You can intertwine this with a name capitalization activity by including the author or writing a brief sentence about the book and having them rework the capitalization where appropriate.
Provide a story without any capitalization and let the students edit it. Make the story short enough for a fifth-grader to stay focused, but long enough for them to use all the capitalization rules they have learned so far. Next to each paragraph, write the number of letters within the selection that should be capitalized. Consider using names, proper nouns, contractions for I and titles. For an added challenge, have them explain why each letter they capitalize needs capitalization to ensure they fully understand the concept behind it.