How many times have you seen an entrepreneur, maybe even yourself, go to a networking event, meet a lot of people, and then leave and never talk to them again? Too often, right? And it’s not because you don’t like them or ever want to see them again, but because you’re a busy person with so much going on that you can barely remember what you had for breakfast, let alone reconnect with individuals you just met at a recent networking event.

It’s a shame because these new contacts are the source of potential future business -- if you bother to start to cultivate a relationship with them.

Don’t be misled by some networking experts -- it’s not the number of contacts you make that’s important -- it’s the ones you turn into lasting relationships that make a difference. I don’t believe in the old adage -- “it’s not what you know, it’s who you know.” I believe that it’s not what you know or who you know -- it’s how well you know each other that counts.

There’s quite a difference between having a “contact” and having a “relationship.” Try making 10 phone calls to people you’ve just met. Tell them you’re putting together a marketing plan for the coming year and you would appreciate any help they could provide in the form of advice or a referral.

Related: Don't 'Stop Networking.' Just Start Doing It Right

So… how well did that go? Not very well I suspect.

Now, call 10 people you know well and tell them the same thing. I’ll bet there are better results behind Door Number Two. Why? Because you already have a relationship with these folks, and depending on how strong that relationship is, most of them would be glad to help you.

So here’s the question: How can you deepen the relationships with people to get to the point where they will be be willing to help you out in the future? Here are four quick steps to get you moving in the right direction.

1. Give them a personal call.

I know this is a crazy idea but -- actually talk to them. Set up a time to do a one-on-one meeting with them. Do not try to sell to them. Set up this meeting to deepen the connection and start to build a professional relationship.

2. Use past contacts.

Make personal calls to all the people who have helped you or referred business to you in the past. Ask them how things are going. Try to learn more about their current activities so you can help them in some way.

Related: 9 Networking Blunders That Undermine Your Reputation

3. Stay in touch throughout the year.

Put together a “touch-point list” of 50 people you’d like to stay in touch with this year. Include anyone who has sent business your way in the past 12 months (from steps one and two), as well as any other prospects you’ve connected with recently. Send them cards on the next holiday, connect with them on social media and stay connected in any other way that you believe they are most interested in.

4. Maintain communication.

Two weeks after you’ve sent them cards, call them and see what’s going on. If they’re past clients or people you’ve talked to before, now is the perfect time to ask for a referral. If they’re prospects, perhaps you can set up an appointment to have coffee and find out if their plans might include using your services.

Related: How to Start a Conversation With Strangers at a Networking Event

Relationships are part of the fabric of the development of your social capital. You must keep investing in the relationship if you ever expect to make a withdrawal. Relationships truly are the currency of the 21st century.