Yesterday, I spent the afternoon at Harvard Business School, meeting with former professors and chatting about what the next year holds for their entrepreneurship curriculum. I'm admittedly envious of what faculty members like Tom Eisenmann have planned for the MBAs this year. You guys are so lucky!

My nostalgia got me thinking about what I wish someone told me before I started my first week of business school. Here are my top 3 pieces of advice.

For some reason, whether it's simple karma or #payitforward in action, important people are more likely to return an email from a student than from your average cold caller. As long as messages are (1) well-written, (2) short [very important!], and (3) cite some sort of common connection, they tend to be well received and can be the first step in developing mentor relationships that will last throughout your career.

An old sage of venture capital once told me, "You don't find a mentor; they find you." But, I think he was referring to the "convincing them" part of the process. Initially, you have to take the initiative to put yourself in front of great mentors, and business school gives you a great platform to do that.

I can't stress how competitive really good jobs are. By the time you're sitting in that interview chair in April of your second year, the statement, "Well, I think I would be a good fit for your company because I'm a good problem solver" won't cut it. Sorry.

You need to be able to actually tell a company why you're passionate about their industry and why you are the best person to solve a particular problem they have. To do that, you need to develop "expertise." I put expertise in quotation marks because, of course, you won't be an expert by the time you're in your second year. Yet, for some reason, the magic of an MBA program is that it creates the illusion that you know what you're doing (so long as you can speak intelligently and passionately about a particular opportunity).

So, the search starts today. Start doing things that build your expertise over time: Set up an RSS reader that follows top industry blogs, schedule coffee meetings once a week with classmates who have worked in your industry of interest and cold call influential executives in your network. By the time the job search rolls around, you will have a leg up on everyone else.

If you're in business school, you probably have a "work hard / play hard" attitude. The problem with that philosophy is that it can leave little time to develop actual, deep relationships with your classmates. Some of my fondest memories in school were the long discussions over lunch, the trips we took together and the hours we spent planning pranks to play on our sectionmates and professors.

Make sure you take the time to have real discussions and meaningful interactions with your classmates. You will learn a ton from them, but you will also develop a few friendships that will last a lifetime.