The average reader spends less than eight seconds looking at the front cover of a book. An agent or publisher spends even less time on the front cover of a manuscript.

Your title has to grab them by the collar, so that they’re compelled to keep reading.

Be provocative

Provocative statements jolt our attention like electric shocks. They make us curious. They make us angry. Most of all, they make us want to read on.
Eg. So You Don’t Want To Go To Church? / So You Think You’re A Great Mom?

Use ‘key words’

Key words grab reader’s attention. However, in the Internet age, here’s another good reason why they’re important. If you’re planning to sell your book online, it’ll help readers to locate your book via subject searches on sites like Amazon.
Eg. Secrets of the Millionaire Mind / Bend It Like Beckham.

Be outrageous

Take a risk. Write without fear of judgment or prejudice. Break boundaries. Challenge taboos. Make people sit up and take notice.
Eg. Sex in a Tent / The Nigger Factory.

Use words that intrigue or arouse curiosity

Books and films offer escapism and fantasy. They provide a chance to experience larger-than-life characters and experiences. A title that hints at a life less ordinary is bound to arouse curiosity and interest.
Eg. The Life & Loves of a She Devil / The Man Who Mistook His Wife For A Hat.

Use pictures or strong visual images to provoke your audience

Use the strong words, colours, or sensory images to stir your audience’s imagination. Use a picture or metaphor to get started.
Eg. The Color Purple / Miss Smilla’s Feeling for Snow / Chocolat.

Use alliteration, rhyme or repetition

People respond to words or phrases that are catchy and memorable. This is why pensioners can still recite the nursery rhymes they learned when they were toddlers! It’s why you can find yourself singing along to jingles, TV ads or pop music even though they irritate you! Love ‘em or hate ‘em, they stick in your head.
Eg. Rich Dad, Poor Dad / What To Expect When You’re Expecting.

Try testing titles on your friends and family, then pick from the ones that are most popular. You’ll be a lot closer to sales success than by just guessing.

It’s worth devoting considerable time and energy to getting this right. Remember that many authors and publishers have used this knowledge before you, to turn sales disasters into phenomenal success stories! Your efforts may be rewarded in the same way too.