[Matrixbeast]

A mild tip when it comes to dialogue is that, when multiple characters are speaking, to move the paragraph down a line. It keeps the flow. Some writers will separate dialogue completely, but I don't think it's entirely necessary. However, if you have long stretches of dialogue with little actions, it might be better.
Anyway, I don't have any real criticisms, but there are some minor errors.

Quote:

Originally Posted by Klonoahedgehog

Meanwhile, just outside of town, the dog monster was eating some of his stolen apples. He was really enjoying them until somebody just yelled out to him. "Diamond Dog! What are you doing?" The dog looked back and stood up. "Sunset Shimmer! I just having a snack!" He took out one apple and held it out to her. "Want one?" She looked at it for a bit and smacked it out of his hand. "Didn't I tell you to eliminate the Elements of Harmony!?" Yelled Shimmer with a blazing fire behind her. He stammered for a bit. "Well, it's hard to find them when avoiding those stinky humans!"
"Then don't! Just straight up destroy them until you find those elements!" She then snapped her fingers and many smaller, dark monsters appeared around her. "Just take these and get out of my sight." She then disappeared in a puff of flames. The Diamond Dog then looked around at the monsters and then looked at the city. "What we waiting for? Go!" And he walked in that direction with the monsters following behind him.

-Slightly edited version of your excerpt.

It's decent.
Try to avoid starting a sentence with a conjunction like "And", though. While I'm not going to deride it, it has to carry a certain sense of flow, and the preceding sentence doesn't lead into it.

As for the excerpt at hand, there are points where I'd make revisions in terms of wording and sentence structure, but for what it is, it's not bad.