Call Before You Need Anything
I worked for a gentleman who told me once a week I should spend an hour per day calling contacts I have in my address book. I asked him why. He said “It’s not now that you’ll need a favor, it’s later and if you haven’t talked to someone in 8 months, when you really need their help, you’ll seem manipulative.”
Swim with the Sharks authur Harvey MacKay has preached that you should have a structured method on how to maintain your relationship with everyone you come in contact with. A bit of work yes, but definitely worth it.
Call before you need anything.