Source.

• Don't spend too much time looking for the "perfect" environment.
• Don't count prep work as studying. (Organizing files, making a timeline/schedule, etc.)
• Don't start with the easy stuff.
• Don't multitask. (Devote one entire study session to one subject.)
• Don't discard the clues. (Take your teachers' suggestions into mind, look over past homework/in-class examples, and so forth.)
• Don't microfocus. (Studying is a process that gains strength by building up speed.)
• Don't just memorize. (Take the time to digest what you're studying.)
• Don't take constant breaks. (Rule of thumb? One 10-minute break for every 50 minutes of studying.)
• Don't forget to take notes throughout the semester.
• Don't blow it off two days in a row. (You're technically supposed to study every day of the week.)
• Don't be too hard on yourself. (It's a gradual process. The most important thing is to stay positive!)
• Don't do it alone. (Go see your teacher, prof, TA when you have questions.)