Study examples of the type of writing assigned. Ask your instructor for sample papers from professional and student writers. Check your campus and local libraries for examples. Don't just read the examples; study them. Look at how the writers tie ideas together, the words they choose, the overall organization, the amount of detail and the format.
Eliminate distractions when you sit down to write. If you must use the campus library to access the university computer network, find a quiet corner. When you work at home, set up a desk or table away from windows and the television. Turn off instant messaging programs on your computer and shut off your cell phone. Consider noise-canceling headphones if outside sounds disrupt your thinking.
Get feedback about your work from friends, family members and classmates. Even if they don't understand the content, they can point out areas that seem confusing or need further explanation. Meet with a tutor if your school offers such a service or find a private program. Find someone who can help you with both content and grammar issues. Ask your instructor to clarify comments and grades you've received for written work.
Take an upper-division writing class. Many colleges and universities provide advanced writing courses for students majoring in topics other than English. Schools offer courses about writing for various disciplines and in particular professions, as well as general upper-level writing courses.
Address your personal demons one at a time. If the difference between its and it's, or there and their trip you up, borrow or purchase handbooks, or access online writing labs to find techniques to help you keep them straight. If you have trouble organizing, look for tips from writing textbooks or tutors and develop a system that works for you.
Practice. A study by Northwestern University found that learning to write well is both conceptual and performance-based. Simply put, practicing writing helps students become better writers. Revise old papers and ask tutors or instructors for feedback about your changes. Schedule study time or write in a journal every day.