The best thing you can do to increase the amount of understanding you acquire from a class is to prepare, and ask questions. This means that when the professor hands out a syllabus, you’re reading one day ahead. You should already have “the reading” done for the next day’s class, and have a piece of paper prepped for taking notes in advance, or at the very least understand what your notes will look like by the end of the class.
I’ll give a short example. In any class taught for the U.S. military’s ROTC program (and I suspect throughout U.S. DoD) there are “samples of behavior” on the syllabus. It says, simply, by the end of this lesson you should be able to “list the three types of …” or “explain the difference between …” etc. When I would go into an ROTC lecture, I would have these sentences (in the imperative tense) written out ahead of time. So my sheet would say:
Explain the difference between “delegating to” and “empowering” your followers.
(three blank lines)
List the three types of counter-value targets.
(and in this set of blank lines, the numbers 1, 2, and 3).
You can see where this is going. When the professor/Colonel answered one of those questions, I’d start scribbling notes in the space prepared. If the professor seemed to have covered a section, but not answered the question I’d written down, I would ask–as directly as I could–if I had missed the answer. For example, “Professor, have we moved past the difference between empowering and delegating?” By the end of class, if I didn’t have all of my blanks filled in, I’d go up to the front and ask the instructor if he had answered that, or if it was in the reading, or if we would be covering it the next day.
“But Jurph,” you say, “the government didn’t give me a list of topics we were supposed to cover!” No, but your professor should have. Use the syllabus as a top-level outline (if you don’t have a syllabus, outline the chapter on your own) and go one or two levels down through the chapter. For example, if the syllabus mentions “Day 3 - Revolutionary War: Reasons, Effects on Trade, and Outcomes” then your outline is pretty obvious.
Other places you can look for outline material include the chapter and paragraph headings in the text (yes, you should read ahead!), or even the first or topic sentence of each section in the text.
For mathematical or engineering courses, your notes usually focus on how to solve certain types of problems, so instead of chapter headings, you might use equation names (“Deriving Bernoulli’s Equations: Energy method”) or problem types (“Determine heat capacity of a convecting surface given rho, V, lambda, T, and Q-dot.”) If your professor follows the text, then it’s a good bet that he or she will do similar (or identical!) sample problems in class. Homework problems will often be close cousins to these sample problems, so you might even look a week ahead at the homework, so when the professor shows you how to derive C from D, you can ask “Hey, how do we derive D if all we have is C?” A good professor will show or tell you; a really good professor will laugh and say “that’s for you to figure out on the homework.” A bad professor will say “that’s not important,” and then put it on the exam.
Most classes fall somewhere in between these two extremes (problem-oriented and narrative-oriented) but you can adapt your note-taking style to fit the situation, as long as you’re prepared. I used this method on and off throughout college, and here’s what I noticed: it took a lot of discipline, I only used it when I thought I was in over my head, and it invariably resulted in me getting better grades. When I got cocky (because of my good grades!) and stopped using this method, I got C’s.
One last piece of advice, which will affect your grade in a college course. Sit as close to front-and-center as you can. In an auditorium, sit a few rows from the front (3d or 4th, max). Strive to be dead-center of the classroom every day, and as close to eye-level with the professor as possible. If you show up prepared and ask questions that show you know what’s going on, you may just be making your own luck for later–if you flub a mid-term or final, the instructor (who knows your face and probably your name by now) is more likely to give you a chance to do extra credit.
You may also luck out: I went to ask about my semester-end grade in Thermo, and the professor looked up my name in his grade-book, and said (I’ll paraphrase) “Your midterms were solid. Your homeworks were not perfect, but better than average. You always knew what was happening in class. I bet you know what you did wrong on the final already. I think the final unfairly penalizes you for a bad day. You are no C student. I can’t make you an A student with this grade, but I think you have earned a B+. Does that sound fair?”
It works.