Here are some examples:
Do not capitalize:
* Can you believe it?
* What be the reason?
* I can do it!
Capitalize:
* Can-Do Attitude
* To Be or Not to Be
* The Can Company
Exceptions:
* If "be" is part of a proper noun:
* Be prepared for the worst.
* If "can" is part of a proper noun:
* The Can-Do Attitude Award
* If it's a stylistic choice:
* Can I Help You? (This is more informal and emphasizes the word "can")
In summary:
* Follow standard title capitalization rules, capitalizing the first word, last word, and all other major words.
* Do not capitalize "be" and "can" unless they are the first word of the title or are part of a proper noun.
* Consider your style and audience when making exceptions.