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A couple of general writing hitches.
Adverbs. Seriously, be terribly suspicious of -ly words. You can usually find a verb that precisely describes the action without the adverb.
"He suddenly stood up."
"He jumped up."
Then there's redundancy:
"He quickly ran to the store."
"Ran" implies "quickly".
Or you're focusing on the wrong thing: "He quickly slapped her." What you mean is, "His slap surprised her."
Something else I fall prey to is action lists:
"She unzipped his pants, reached into his shorts, pulled out his cock, and kissed the tip."
Bleagh. Try: "After taking his cock from his pants, she kissed the tip."
Or go into detail with intent:
[[She fumbled his pants open, but as she fished his cock out, it scraped on the zipper.
"Oh, I'm sorry," she cried, and without thinking, kissed the offended member.]]
Practice reading published works to see how your favorite authors do things. The story will be distracting at first, but you need to learn to see the leaves and branches as well as the forest.
A note on OP's complaint concerning "comic book" dialog. Excellent point, anon. I myself have a habit of using... ellipses, to indicate hesitancy, or a character editing their thoughts as they speak. It's good spice in moderation, but easy to overuse.