As you're taking notes during a lecture, listen for clues from your teacher about which information is most important -- don't try to write down everything verbatim or you may miss something important. When your teacher says something like "This will be on the test," draw an asterisk next to that information in your notes so you can easily find it when you're studying.
Everyone learns differently -- some people are active learners, some are reflective learners, some are visual learners and so on. Knowing how you learn best can help you in class. If you are visual learner, for example, you can use this knowledge to help you better retain information during lectures. Even if your professor is not using visual aids, tailor your notes to your visual learning style -- drawing pictures, for instance, to help you remember concepts, or using shapes to organize your notes. In a geography class, you could draw boxes around information that pertains to Russia, circles around information that pertains to France and clouds around information that pertains to China. You can similarly color-code your notes by highlighting different categories of information using various colors of markers or removable sticky tabs.
It's easy to get distracted during a classroom presentation. The University of Minnesota Duluth offers several suggestions for staying focused. One tip is maintaining eye contact with the professor when you aren't taking notes -- this helps keep your mind from wandering. Another strategy is asking yourself mental questions while you listen. Listen actively by asking yourself things like "What point is my teacher trying to make here?" or "How does this relate to what he's taught us in other lectures?" Another tip is focusing on the content of what your professor is saying rather than his delivery. If you find yourself thinking about how your professor says "Um" a lot or the fact that he plays with the chalk while he's talking, you're not focused.
Take note of the atmosphere of the classroom, because this can help you later while you're going over lecture notes. If the air conditioning is on and your classroom is often cold, review your notes in a cold room. If your class takes place right after lunch, eat a snack before you begin studying. Studies have shown that duplicating the classroom environment as much as possible can help you remember more of what you learned in class as you're studying.