
Certain genres are renowned for being more suspenseful than others:   horror, crime fiction and romantic suspense, but each and every book, no   matter whether it's an Historical Romance or a Paranormal Fantasy, HAS   to have a level of suspense interwoven between the pages!
All  stories need to have this element, otherwise the reader isn't going  to  want to turn the page, it's as simple as that. So if you're  interested  in what makes a suspenseful page turner, then please read  on... 
Creating conflict in your novel is a given, otherwise there  would be no story. If all went smoothly it would be as  dull-as-dishwater, wouldn't it? They all lived happily throughout the  story and ever after, yawn...
I've listed seven ways you can inject suspense into your novel:
1. Introduce your characters to their worst nightmare!Find  out about your characters beforehand. If possible, write up their likes  and dislikes etc, and most importantly of all, find out what it is they  fear most? What is it that causes their hearts to thump loudly, beads  of perspiration to form on their upper lips, and the hairs on the back  of their necks to stand on end? Find out what that thing or things are,  and then give it to them, both barrels. For example, if your heroine is  petrified of flying because her parents died in a plane crash, create a  story where she HAS to take a journey on an airplane. If your hero fears  water because he almost drowned as a young child, put him in a position  where he HAS to get back in the water to rescue someone.
Introduce them to their worst nightmare and watch how they react!
2. Lull them into a false sense of securityWhen  your character is really frightened of something, throw in a red  herring. For example, if your heroine thinks she hears a noise outside,  allow the plot to let her fears grow and grow. Let it be something quite  innocuous, like the dustbin blowing over in the wind. Then, when she  has reassured herself, breathing a sigh of relief, petrify her to death  by placing a prowler outside her back door!
3. Throw the spotlight on at least two peopleThis  might sound a little obvious, but for goodness sake, don't make the  villain of the piece stand out a mile. Instead, have suspicion fall on  at least two, possibly three characters. This will have the effect of  your reader not really being sure until the end, when the other shoe  falls! But, by all means, leave some clues and some red herrings along  the way!
4. PacingPacing is  important to create suspense. In general, short, snappy sentences will  enable the reader to race ahead so they feel their heart is beating in  time with the frightened protagonist. Longer sentences tend to slow  things down. You might want to speed things up for a car chase or slow  it down for a love making scene. Imagine your novel as if you were  watching it on the big screen. How would it be filmed? What would that  particular scene look like to the audience?
5. The calm before the stormMake  use of the weather to good effect. Thunderclouds brewing overhead,  often give the reader the feeling that something is about to happen  [prophetic fallacy]. A bolt of lightening hitting the night sky, power  lines down, a stranger at the door, etc. Think of the last time you  watched a horror film; didn't the weather come into somewhere?
6. When all goes well, throw in a dead body!When  you hit a sagging middle of a novel, and you find there's no where to  go, try throwing in a dead body. This doesn't necessarily mean that a  character has to be killed off, although you might want to do just that,  it can mean that something unexpected happens, such as the birth of a  baby, etc. Something that injects a little more oomph into the plot!
7. SettingSetting  is very important as a tool to create suspense. What about that dark  stone staircase covered in cobwebs? Or the elevator that suddenly stops  in between floors? Choosing the right sort of setting can make or break a  novel. And sometimes, placing the object or person the protagonist  fears in an innocuous setting can make the story all the more  horrifying.
Be cruel to your characters and watch them run for their lives!