1) First and most important - create and describe characters that readers will care about. If you don't, no-one will engage with your story, no matter how clever the plot,
The Insect Farm
2) Have a "big plan" but don't try to plot all the details before you start writing - it's fun to dream up some of them as you go along.
3) Try to review what you are writing as though you were a new reader. If you think you know what is going to happen next, change it.
4) Maybe trickiest of all - try to leave enough clues as you go along to keep readers engaged in the mystery, without giving away the whole story.
5) Leave clues which will make experienced readers of mysteries think they know the answer, and then make it something else.
6) Find yourself a good agent who will take the time to tell you what you're doing wrong, and then take notice of what he/she says.
7) Find a publisher who understands and supports what you are trying to do and will take the time and trouble to help you to do it.
8) Choose a title which will intrigue and make people want to pick up the book.
9) Listen to advice about the cover - chances are the publisher understands their market better than you do.
10) Never stop revising or rephrasing until the moment your manuscript goes to press.