Suspense is created through many ways in 'The Stepfather'. For example in one part of the film suspense is created through normality. In the start of the film we see a man who seems like a normal family guy. We see him shaving off his beard and showering but this is just building up to what we see later on in that scene. He puts on the radio and eats his breakfast. The song 'Silent Night's is played there but then it becomes subverted, tense psychotic music stats playing in the background, then the dead bodies appear and it shows a flashback of a teenager.
False Plateau is used in one part of the film. When the old lady's doorbell rings she goes to open it to find nobody there, then a cat jumps out infront of here, the audience probably expected the killer in this part, we are relieved that it wasn't the killer but a cat, then the actual killer comes and throws her down the stairs then chokes her.
At the end of the film suspense is created through bomb theory. We see that he meets another woman knowing that he is a serial killer but she doesn't.