1) Easy to say.
Who wants to look stupid when ordering or discussing a book?
2) Easy to spell.
If someone is searching on Amazon or Google and they get the spelling wrong, then the search engines won't find them.
3) Uncommon words
My name, Sarah Duncan, is fairly common. If someone does a Google search for me, my website does come up first, but there are lots of other Sarah Duncans around, as well as "...said Sarah. Duncan, on the other hand..." If your title has lots of common words then it's going to be harder to find on search engines.
4) Strong nouns
If I say "the book about the tractors", I bet most of you will know the book I mean. In fact, Penguin used that line to advertise Marina Lewycka's next book. (And I don't know how you pronounce her surname either.)
5) Fits in with the genre
The Guernsey Literary and Potato Peel Pie Society doesn't sound like it's a thriller or teenage vampire book. In Cold Blood doesn't say romance. Titles need to match the genre.
6) Has some originality or quirkiness
Would Captain Corelli's Mandolin have done as well as The Italian with the Guitar?
More on finding the perfect title tomorrow...
Come to the launch party for Kissing Mr Wrong, 6.30pm on 20th May at Waterstones, Milsom Street, Bath. All welcome, but please ring 01225 448515 to let them have an idea of numbers.