You can also use the power of the unknown. Don't reveal too much too soon. Just give hints about what might be out there. For instance, the character hears a growl, but they don't know what kind of creature it could be. Is it a wild animal? Or something more sinister? Also, create a sense of isolation for the character. If they're alone in a big, empty place, it adds to their vulnerability and the tension of the situation. And don't forget to use short, choppy sentences when the action starts to pick up to increase the sense of urgency.
The story could build tension by creating a sense of helplessness. In the diary, if the girl is in a situation where she has no control, like being trapped in a haunted place. Also, the pacing matters. If it slowly unfolds events, like she starts to notice a strange smell in the house one day, and then over the next few days, other strange things occur, it builds tension. And the use of foreshadowing, like she mentions a strange dream before the real horror starts, can also build tension.
One way to build tension is through pacing. Slow down the story when something spooky is about to happen. For instance, if your character is approaching a haunted house, describe every step, every breath they take. Another method is to use short, choppy sentences when the danger is near. Like 'She heard a noise. It was getting closer. She couldn't move.' This makes the reader feel the character's fear.
They build tension by being unexpected. When you least expect it, you hear those footsteps, and it immediately grabs your attention and makes you feel on edge.
Using the element of time can be very effective. If you set a deadline or a ticking clock situation, like the protagonist has to get out of a haunted place before sunrise, it creates a lot of tension. Every second that passes makes the situation seem more and more dire, and the reader feels the pressure along with the character in the story.
You can start by creating a sense of uncertainty. Make readers wonder what's going to happen next. Also, build up to important events slowly to increase anticipation.
One way is to use slow pacing and build up suspense gradually. Let the reader or viewer wonder what's coming next.
Tension can be built by introducing unexpected twists and turns. Maybe a trusted ally betrays the protagonist or a seemingly easy solution turns out to be a trap. Additionally, ratcheting up the stakes for the characters makes the story more tense.
One way is to introduce time pressure or deadlines for the characters. When they have to act quickly, it naturally creates tension.
One way is to create a sense of time pressure. Make the characters have a limited amount of time to achieve their goal.
You can build tension by creating time pressure for the characters or introducing unexpected obstacles.