The date of March 15 has long had a black eye reputation. William Shakespeare is largely to blame. He took the famous date when Julius Caesar was murdered, and turned it into the catchy phrase "Beware the Ides of March." It's a phrase that's come to mean watch your back, don't assume all is well, and check your ego. But its meaning is greater, especially for entrepreneurs on the rise. As March 15 approaches, it's worth revisiting what it takes to go from successful entrepreneur to exceptional leader.

Caesar too was a bold visionary and a strong, even cocky leader. And prior to that fateful day, he'd had a lot of success doing his version of "scaling the enterprise." But he got caught up in his success, let his guard down, and then he was done. The deeper lessons behind his fall are evergreen and the very things entrepreneurs with early success ought to take note of if they want that success to continue.

Be conscious of the limits of your brilliance.

It's not unusual for entrepreneurs to reach a level of high self-confidence. Just consider their early journey to success. They stand alone to make their case when no one yet believes in their brilliant idea. Especially early on, their sweat equity is the greatest, their nights the most sleepless, and their risks the highest.

So, it isn't hard to see why they slip into feeling they are the most capable, even brilliant. Yet somewhere inside each entrepreneur is the knowledge that many build a venture, not just one. And the further a venture progresses, the more one person's ability to have all the answers declines. Bottom line, check the facts about what drives success, then check your ego. You'll quickly discover you not only need others, you need them on equal footing if you want to keep success going.

Forget the idea of being the entrepreneur.

The entrepreneur as we most often hear about him or her is an urban myth. That myth begins with the falsehood, (noted above), that there is but one source of brilliance from beginning to end. But it goes further to feed the false burden that you alone must lead every charge, make every decision, and carry the full weight of the venture's success ongoing.

The sooner you let go of the myth, the faster you build the all-important entrepreneurial team it takes to scale a venture. By team, I don't mean all the people you hire to fill empty slots on your org chart and do your bidding. By team I mean a culture of people who see the venture as equally theirs and equally their responsibility to make it succeed.

That's ownership beyond a stock certificate. It's the ownership that defines, fuels, and hones true competitive advantage in the form of a shared purpose. That collective ownership, that shared purpose, is what generates the breakthroughs ongoing. If you think the story is all about you as the entrepreneur, you're living a myth.

Play on the field you're dealt, no matter how great your plan.

The most important Ides lesson may just be this: No matter how good you or your plan are, no matter how well it's all working in this moment, expect the environment to shift, and let yourself and your plan do the same.

Go one better: train your culture for such conditions -- not just to be ready to react when unexpected change comes, but to see change as advantage. Entrepreneurs have a strong tendency to get lost in their plans, especially when they find one that works. They shift from meeting a need in the market with flexible and innovative thinking, to defending turf hard won. But plans support, they don't lead. And plans, good ones at least, are designed to take advantage of the prevailing conditions of a marketplace.

If you forget that and ignore a changing field of play, you might as well be standing on the steps of the Roman senate, taking in the Mediterranean sun on a mid-March day, with your back to the reality looming behind you. Environment first, plan second. Period.