Continuing Jeff's train of thought from last week's "Mistakes We've Made" column, I thought I would add a caboose today that includes some thoughts about a few of the investing lessons I have learned over the past two years. I've learned many, but I'll only focus on three in order to not be too much of a self-centered bore. Hopefully, some of these points will resonate with the younger investors out there who, like me, are just starting out on their lifelong investing journeys. If not, well, maybe the Breaker Port will have something more interesting to say tonight. It's not like we're charging you a quarter every day to read this or anything.

Point #1 -- Price does not equal value

This truism is the Pythagorean Theorem of investing. Just because the share price of a company you happen to own rises on a given day, that doesn't necessarily mean that the company's real value has increased in lockstep as well. Of course, the reverse is also true.

We see this principle play out in the stock exchanges every trading day. In fact, the Fool's entire News & Commentary area is devoted in part to exploring this concept in action. However, the point was really driven home when I watched the only stock I currently own, Intel Corp. (Nasdaq: INTC), rise from $50 per share to $90 per share between June 1 and Sept. 1 of last year. Why? Beats me. I had pretty much the same opinion about the stock in September as I had in June.

That the Drip Port has often dwelled on the difference between price and value is somewhat counterintuitive considering the philosophical underpinnings of our investing process. In my opinion, dollar cost averaging -- especially the mind-numbingly consistent form termed straight dollar cost averaging by George L. Smyth in a column this week -- serves to marginalize the importance of the price/value dichotomy. Still, if a mad horde of laconic editors were to storm the Fool tomorrow and limit the Drip Port's daily commentary to only 10 words or less, Warren Buffett's timeless saying that "Price is what you pay, value is what you get" would get my vote for an eternal run.

Point #2 -- Investing is not about making money. It is about making the best possible return on your money.

Taken alone, the action of buying stocks won't make you rich. Fortunately, I've learned this vicariously and not through any dumb-witted actions of my own in the market over the past two years. Still, I'm sure my remaining years on this planet will provide plenty of opportunities to screw up royally and re-learn this lesson over and over again.

This point gets at the real reason why we invest in stocks at all. It's not to impress our friends, it's not to feel part of "the in crowd." Rather, stocks offer the best opportunity to achieve the highest possible long-term return on our money. Higher than passbook savings accounts. Higher than bonds. Higher than real estate. Higher than Beanie Babies and Pok�mon cards.

Exactly how to think about this superior "returnability" of stocks was best expressed in a series of columns written a few years ago by Drip Port co-founder Randy Befumo, collectively entitled "The Dollar Machine." (Part 1, Part 2, Part 3; scroll down past the Heroes and Goats.) These articles also make a strong case for why investors should think like share owners, not stock holders.

Reading these articles was one of my first "homework assignments" when I started working here at the Fool two years ago. Since then, I have re-read them numerous times. In hindsight, I knew that I was ready to invest on my own when these articles started to make absolute crystal-clear sense, which was only a few months ago.

Point #3 -- Investor, know thyself.

This is undeniably the most important lesson that I have learned in the past two years. Not coincidentally, it is also the one that has taken the most time to learn. Knowing yourself is important in any of life's pursuits, but in investing it can make all the difference in the world.

Rather than thinking "Do I have the right stuff to beat the market year after year" or some other unknowable, place yourself in the following scenario. Imagine a train takes you to a town in the middle of nowhere where you know nobody, have no inside connections, and must either sink or swim based on your cunning in business. All you receive is $1,000 and the order that you must start a business. What business would you start? How would you make it successful? In five years, where would that business be?

Of course, we can't all be successful businesspeople. But truth be told, there is little difference -- in regards to one's mindset -- between running your own business and running your own stock portfolio. Both require making capital allocation decisions. Both require accountability for your actions. Both require the acceptance of a certain degree of risk. And certainly, both require a lot of work. Figuring out whether or not you are realistically up to the task BEFORE dropping your first dollar into a stock may be the most lucrative and rewarding lesson of all.