Writing that kicks you. Writing that keeps you awake from sheer mad joy. (Thank you, Jack Kerouac.)
If there is a secret, this is it. Just do it for the kicks.
A few things about suspense: let the reader know more than the characters. The character who knows the least about what is going on has the most suspense. This does not apply to the reader. Let the reader know what you know, and don’t try to create suspense by withholding information. I think it was Louis B. Mayer who said, “Make ’em laugh. Make ’em cry. Make ’em wait.” This is not bad advice, but it becomes artificial if you hold back information crucial to understanding what the hell is going on in your story just because you think it will make the story “suspenseful.”
I think this is true, but I could be wrong. As Musashi says, “think deeply on these things.”