Suspense is based on the audience expecting something scary to happen. Basically, suspense is the moment between cause and effect, and one trick is to simply extend that time. Pick that scary something, like, say, a monster appearing. Describe the elements of the monster one by one. Don't say too much at once, and don't say nothing at all or else it will become boring. If the monster has claws, show bloody claw-marks first, and then maybe the fang marks, and drag lines on the ground where the victim was pulled. Maybe you hear a low growl first, then the footsteps, then a slightly louder growl.
To sum up: for suspense, make every reveal a process, rather than an event.
Within each shot in the process, use whatever lights/shadows/blood trails/torture equipment/sounds that will make the effect you're suspending seem as bad as possible. Terror is infectious. A scared character will help scare the audience.