Creating fear in your readers: Don't go into the woods...
Warning: this article contains clowns.
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Think of tricks as simple as long sentences and paragraphs that gradually get shorter in length.
I actually do this. Another thing I do is play with grammar. If someone is out of breath or talking quickly, then sometimes I add/remove a comma/period/appropriate piece of grammar. I even do it outside of dialogue, given that I tend to write in limited 3rd, so, theoretically, you're hearing the character's thoughts and seeing what the character sees, anyway. Typically if I play with grammar within a character's thoughts, then they're mentally jumping from one idea to another or having a hard time wrapping their mind around something that happened.
Repetition is the other thing I do, depending on the character. (I say "depending" because if something stressful is being shown through Rus's POV, I've found that there's a lot of repetition of words and phrases, compared to Benito's POV, who barely repeats anything. I might have to find an example.) The only thing about repetition is making sure it comes naturally. It's almost more difficult than shortening sentences/paragraphs/etc because if you pick the wrong thing to repeat, then it just becomes annoying. But I have a weird love for repetition, so. :P (I wrote a story with the most repetition I could possibly create that didn't feel forced or awkward.)