It is important to know your topic before you begin writing in order to avoid either missing the purpose of the assignment or veering off track. While anecdotes or asides are appropriate in some contexts, you must link everything back to the main point. The best way to avoid missing the topic in your writing is to create a thesis statement that aligns with the assignment, then build an outline of your ideas before you write. Stick to your outline and thesis statement throughout the writing process.
Passive voice is one of the main weaknesses in college essays, and is generally not appropriate for assignments. Always strive to use the active voice. Passive voice, such as "the room was left cluttered," does not emphasize the doer of the action. "Jamie's room is cluttered," in contrast, begins with the subject of the sentence, and is much more engaging. Using passive voice takes away from your writing, and often results in wordiness and imprecise language that is difficult to understand. One of the only exceptions to this rule concerns essays written in the sciences, where passive voice is more accepted.
Cliches are known as cliches for a reason -- they are over-used. Using these phrases does not generally strengthen writing because the reader has heard them before. Professors may also assume that you did not entirely articulate what you were attempting to say when you use a cliche. If you find yourself using a cliche in a draft, revise by creating a metaphor to make the same point, or think of how you can be more specific to explain your ideas.
Sometimes papers become too wordy while other college papers do not explain enough. Professors frequently assign papers with a minimum page requirement, which can cause students to repeat themselves in order to fill the space. It is the rare professor who is fooled by fluff and filler. Try to find more information to cover your page requirements. Use specific words and identify what you are talking about to avoid unintended vagueness.
Verb specificity, or lack thereof, is a common problem in college papers. Unspecific verbs make the reader unsure of the message the writer is attempting to get across. Be careful to always use specific verbs which state the action taking place. For example, instead of saying "he went over there," say "he ran over there" or "he walked over there." Verb problems also occur when writers mix tenses, writing some sentences in the present tense but others in the past. Different disciplines have different rules for which tense to use, but a general rule is to choose a tense and stick to it throughout the entire paper.
Check your own grammar and punctuation to avoid errors in your writing. Computers are machines that are not native speakers of a language, so they cannot always be relied upon to catch mistakes in grammar, spelling and punctuation. The best way to avoid turning in a college essay with mistakes is to proofread. It is often helpful to print the draft of your essay, walk away from it for at least a few hours, then read through the paper with a pen in hand looking for mistakes. Some also find reading the information aloud helps.