Questions about writing pop up all the time, and we don't always have the answers. When do I capitalize the word 'mother'? What's the correct abbreviation for 'ounce'? The Writer's Handbook has all kinds of answers to questions about writing. It covers rules for spelling, capitalization, punctuation, and grammar.
CAPITALIZATION is not likely to leap to the top of any teacher's list of "My Favorite Units to Teach." However, it is possible to teach students to capitalize correctly, without having them fall asleep over their text - if you are using a text designed with real kids in mind, and if the text leaves students some room to exercise their own creativity. Capitalization definitely does both.