Since it's back-to-school week, I thought this would be a good time to remind the college-bound (and recent graduates) that this is the time when you lay the groundwork for the rest of your life. Here are some known pitfalls that Millennials should try to avoid:

1. Paying the wrong dues.

Every career has an apprenticeship in which you're not paid much but you're learning like crazy. If you're doing what you truly enjoy, it's worth paying your dues. If you're doing something that you secretly dislike or find boring, that investment of time and effort is a total waste. Even if you become wildly successful, you'll be dissatisfied and be forced to start over.

2. Never starting a business.

In today's business world, job security is a joke and everyone is a freelancer. If you've never even tried to start a business, you'll always think of yourself as an employee rather than an entrepreneur. Creating at least some kind of business (even if it's small scale) weans you from the debilitating belief that you need a job to make money. There's simply no experience that's more valuable.

3. Failure to save long term.

Given current trends, by the time Millennials are ready to retire, the "0.1 percent" will have looted or gutted Social Security, Medicare, and all the other government programs that benefit the less-than-obscenely-wealthy. So unless you were lucky enough to have been born with a diamond-crusted spoon in your mouth, you'd better start saving for retirement now, or you may end up "retiring" in the gutter.

4. Marrying your college sweetheart.

Yes, yes, I know, I know. You're in loooooooooove... I hate to sound cynical, but if you get married now, chances are in a decade or so you'll barely know, or even want to know, the person to whom you're married. (There are exceptions to this rule, of course.) Divorces are easy to get, but they're always emotional and financial disasters. The old saying still rings true: "Marry in haste; repent at leisure."

5. Accumulating more stuff.

Since you were a wee babe, you've been programmed to be a dutiful consumer. However, if you don't break the habit of buying stuff now, you'll eventually end up with entire rooms and storage units full of useless crap. I recommend this simple rule: "For every object that enters my life, I will trash or recycle something equivalent."

6. Never learning to sell.

Success in business or the arts is always proportional to your ability to sell your ideas and the value of your work. If you don't learn to sell, the only way to make big money is by selling out--pretending to be somebody that you're not. Unfortunately, most colleges--even business schools--don't teach how to sell, which means you'll need to acquire this vital skill on your own. A good start is signing up for my free weekly newsletter.

7. Not taking a year off to travel.

If you're the type of Millennial who's reading, you've probably had your nose to the grindstone since preschool. Travel (especially on the cheap) is the best way to figure out exactly who you are and how you fit into the world. So if it's at all possible financially, you owe it to yourself to take a break between college and your first real job.

The above list, BTW, is based on my personal experience. I made all of these mistakes and saw most of my boomer contemporaries do the same. I later made necessary course corrections, but it would have been easier, if I'd had the courage to trust my gut, when I was younger.