1. You shouldn't use the "you" formulation. "You can see..." No. "One can see..."
2. Be careful not to over-generalize. Be specific. Except where one needs to be general.
3. Make sure paragraphs have logical coherence.
4. Avoid slang, and contractions.
5. Always ask yourself, while writing, and proof-reading: Why? How? Where? When?
6. Ask yourself, while writing: What am I trying to say?
7. Get the facts correct.
8. Spell author's and characters names correctly.
9. End the paper on a conclusive note, with new, deeper sense of your own thesis.
10. Have a thesis (form and meaning, both, not one, or the other without either).