1. Which words do you capitalize in a title?
We cap all nouns, pronouns, verbs, and adjectives. The tricky part comes with conjunctions, prepositions, articles, and adverbs. Here's the rule I learned more than twenty years ago and have held to it. The Chicago Manual of Style disagrees.
If any of those other words is five or more letters, cap them; if not, don't. For example, with my book Unleash the Writer Within, I capped the verb (unleash), the noun (writer), and the adverb (within). The is an article and unless the title begins with an article, we don't cap it. Within is more than five letters long.
Here's the way Harvest House printed the title of my latest gift book: Saying Goodbye: Facing the Loss of a Loved One. They capped the words I would have.
However, some publishers establish their own rules. For example, the book I wrote for Eva Piper and published by Thomas Nelson has the title with almost every word and every letter capped, including the subtitle, and used bold as indicated: A WALK THROUGH THE DARK: HOW MY HUSBAND'S 90 MINUTES IN HEAVEN DEEPENED MY FAITH for a LIFETIME. I have no idea why they put "for a" in lower case. Their decision.
Here's a good rule to remember when we write for publication. Look up what you can, and online resources are abundant. If there are different opinions—and there usually are—make your choice and stay with it. If your choice isn't what the publisher wants, it's a minor task for them to make it conform to their standards.