Capitalization Rule- Capital letters are used at the beginning of a sentence, for a proper noun, words derived from proper nouns, the first person pronoun "I" and all its contradictions(I'll, I'm, ect.) and may be used to show respect.

Examples-
I am going to the Grand Canyon.
The only language I speak is English.


http://www.grammarbook.com/punctuation/capital.asp
http://www.kimskorner4teachertalk.com/writing/sixtrait/conventions/capitalization.html
http://grammartips.homestead.com/caps.html
http://www.say-it-in-english.com/BasicEnglish8.html
http://owl.english.purdue.edu/owl/resource/592/1