Perhaps it has been a few years (or decades) since you strolled your college campus on the path to responsible adulthood and a decent internship. But the lessons learned during those four-plus years can continue to serve you well in your wallet.

Let's take a moment to reminisce.

Lesson No. 1: Trying to make up for lost time by cramming doesn't work. How many times were you up at 4 a.m. the night before an exam, six cups of coffee in you, looking at material for the first time? There's no substitute for keeping up with the reading from the beginning if you really want to learn it. So, too, with investing for your retirement: You can't cram all your savings in at the last moment. (Just look at the example of Patrice and Bianca in our Investing Basics area.) Start early and develop good saving habits. And thank your lucky stars that your 401(k) paperwork is multiple-choice.

Lesson No. 2: You get just as much credit for passing the easiest courses and you get to sleep later. Whether they're called TV in Our Society: the History of Soap Operas or Modern Clothing Theory, there were some awfully easy courses that didn't require a whole lot of effort to keep up with. So, too, in investing. Some of the best investments are what we call "obviously great investments" -- investments like Coca-Cola (NYSE:KO), the Gap (NYSE:GPS), and Microsoft (NASDAQ:MSFT). Heck, go ahead and use the investor's version of CliffsNotes and go with an index mutual fund. You don't have to find companies that you'll never understand in order to invest well.

Lesson No. 3: Marry the one with the good personality, not the really, really hot one. How much time did you spend daydreaming about the best-looking guy or gal in your class? If you're even remotely normal, the answer is "a lot." But it's usually not the hotties who will bring you a lifetime of happiness. So, too, with stocks: The hot highflier is not too likely to reward your long-term faithfulness.

Lesson No. 4: A little self-discipline goes a long way. Did you experience the "freshman 15," that extra 15 pounds of weight that mysteriously attached itself to you while you were too busy having fun to notice? In life, credit card debt somehow, mysteriously, manages to do the same thing if you're not looking (if tuition didn't already drain your bank account). For either of these problems, the lesson is that it's easier to acquire the weight than it is to burn it off. (If you don't believe us, just check in with the Fools Fighting Fat.)