Learn how to create a system for keeping in touch with friends.
I keep my address book on my desktop machine. You can use a web-based service, but make sure you can download the information in a usable format in case they go out of business or you want to move to a different service.
When Keeping Up with Friends, Make it Interactive
We relate by interacting. Tweets and Facebook status updates are one way. They remind people you exist, but they only strengthen a relationship when they lead to a back and forth conversation. That doesn't mean don’t do them; it just means they're better for maintaining—not building—relationships. It's like a yearly holiday newsletter. "Here's a message I'm sending to 400 people telling you what's going on with me. I hope you feel special."
That isn't a back and forth; it's more like G-rated exhibitionism. When you contact your friends, ask what's going on in their life, and be interested. Make it about them.
Choose Your Medium for Closeness
Getting together in person builds the strongest connection. Calling or using video chat is next best. Email and letters are good for exchanging information, but often build an illusion of closeness, not the reality.
Try to meet your closest friends in person at least once a year. Call and chat or leave voicemail saying "Thinking of you. Thank you for being my friend!" For people you don't like, just sign them up for a subscription to Nasal Fluids Explained.
Set up a Contact Schedule
Contact people regularly. If your address book allows it, add a NEXT CONTACT DATE field to each person. Put in the date you next want to contact your friend.