[quote=Robeatics]Add little ‘cushion’ to the sentence, and make the action be read as quickly as you want it to be done physically. Let’s say a man is having a gun pointed at the head of his friend. The reader is on a precipice. Will his friend die? Shock your reader.[/quote]

Definitely recommend this. Comedians keep the crucial words in their punchline to the very end so the suspense isn't broken until the end of their last sentence. Perhaps use a similar technique? I love dashes (-). They're basically always grammatically accurate, and imply an abrupt pause.
[indent]Paul was angry. He's never been so angry in all his life, not even when his sister had killed his pet rabbit out of pure spit - he punched Susan in the head.[/indent]
A crude example off the top of my head, but the dash forces the reader to stop, and then continue onto a short, violent burst of a sentence.

I recommend, and this is dull advice, but looking up comma, full stop, speech mark and apostrophe usage, as well as tenses (particularly the difference between Perfect, Imperfect and Pluperfect). On the whole, you're accurate, but there are mistakes, and, where it comes to SPaG (Spelling, Punctuation & Grammar) there's only a small margin for artistic license on the far end of just being plain wrong. Nobody is perfect, everybody makes mistakes, and there's no substitute for proofreading again and again and again, but if you don't know your stuff, proofreading gets you nowhere.

Try interspersing a section of dialogue with a 'stage direction' every so often - it breaks up heavy back-and-forth conversations nicely:
[indent]"You're very naughty," the teacher smacked Icarus across the chops, "Stop being a fuckwit."[/indent]
The 'stage direction' gives both information about what's happening, and implies the teacher is angry - very efficient.

While Robeotics says avoid clichés, and this is good advice, I'd say it's permissible in speech. People do speak in clichés. I do. So will many characters. The narrator, unless it's written from a very personable narrator that's supposed to really come across as a proper character, should not, however.