A few writing tips:
1. When done writing, read the article aloud to yourself. This will help you catch a lot of errors which might easily be missed after having looked at a wall of text for an hour.
2. Always, always, have a friend proof read the article.
3. Sleep on it. When you're done writing, put it aside for a day or two, and re-read it when your mind is 100% fresh and you've forgotten the details.