You've just met someone new at a networking event, industry conference, or a meeting, and the two of you really hit it off. So, as you're wrapping up your conversation, you exchange business cards and tell each other that you're looking forward to keeping in touch.

After that? Well, if you're like most people, that business card finds its way into the dark recesses of your desk drawer -- never to be used again.

Sure, you'll strike up a friendly discussion if and when the two of you run into each other again. But, beyond that, you don't do much to follow through on that introduction and forge an actual professional relationship.

This is a mistake that so many people make when networking -- they have no issue meeting people, but they neglect to use that as the launching point for any sort of continued bond.

Of course, if you're aiming to expand your web of contacts, that's not the way you want to continue going about things. Instead, do these three key things right after you meet someone new, and you'll be far more likely to build a network that's actually valuable -- rather than just an assortment of random connections.

1. Jot Down Some Notes

Perhaps you found out that person is currently training for a marathon. Or, maybe she expressed an interest in exploring a different career field. Right now, all of those tidbits are fresh in your brain.

But, three months from now when you run into her at the appetizer table or she wants to get together for coffee? Well, you'll have a much tougher time recalling the information you've already learned about her.

This is why it's so helpful to spend a few moments jotting down some important notes about the people you meet. Whether you want to store them digitally (I use a list on my phone!) or simply note them on the back of that business card, having that information will be a huge asset to you.

You'll be able to use those random facts to strike up relevant conversations in the future -- and, you'll seem attentive and like you're really on top of your game when you can ask a targeted question about something she mentioned months ago.

2. Send a LinkedIn Request

If you're one of those people who set up a LinkedIn profile and then promptly left it to collect cobwebs, this piece of advice is for you.

LinkedIn is a social network -- meaning it's a great way to keep in touch with the people you meet in a friendly, convenient, and low-pressure environment.

So, after you've met someone that you think could be a beneficial professional contact for you, send an invitation on LinkedIn, along with a personalized message about how much you enjoyed meeting him.

That way, you can stay in touch by doing things like leaving comments and liking his updates. While it's not quite as personal as sending an email or setting up a coffee date, it's still a good way to keep that relationship warm.

3. Set a Reminder

Another thing I like to do after I've met someone that I'd like to keep in touch with? I mark a date in my calendar -- usually a couple of months after we first shook hands.

When that day arrives, I reach out and touch base. Sometimes it'll just be a friendly email asking how things have been going. Or, sometimes it's a link to an article that I think that person would find interesting.

Either way, it's important to remember that relationships -- both professional and personal -- take work and an investment. And, that's a commitment that you can easily let fall by the wayside unless you consciously set aside time for it.

Your goal in networking isn't just to meet people -- it's to forge relationships with them. Do these three key things after you meet somebody new, and you're sure to build a far more beneficial professional network.