Writing the Paper
Avoid logical errors! If you're writing an opinion or persuasive essay, you'll be attempting to convince the reader of your position; don't mess it up by committing a logical fallacy. You'll generally be exposed to common fallacies in a freshman-level composition or speech class; some common ones are ad hominem (attacking the person rather than the argument), slippery slope (if we take the first step, all the rest are unavoidable), appeal to authority (just because famous person X says something, doesn't mean it's true, especially if X isn't an expert in that area), ad populum (everyone believes this, so it must be true), begging the question (assuming what you're trying to prove), and straw man (arguing against a different argument than the one that was actually made), but there are many more. It's worth familiarizing yourself with false dichotomy, non sequitur, post-hoc ergo propter hoc, and tautology as well.
Avoid awkward sentences: read your essay out loud to see if it makes sense. If it sounds awkward when read aloud, you should probably revise it. It's often easier to hear errors than it is to find them when reading silently.
Make sure your spelling and grammar is correct. Don't rely on spell-check to find your errors! This lion eye no is rite; my spell Czech tolled me sew!