The next best network contacts are also close to home—all your friends who graduated last semester or last year. These are college grads who have (hopefully) just completed their successful job search. Unless they burned or buried their notes when the job offer came through, they probably have scores of potential contacts whom they worked long and hard to dig up. Think of it as using last year's chemistry final to prep for this year's final. They have all the "class notes" that will get you off to a quick start. In addition, they are often well placed in the field and can give you insider support like no one else.
Job search is a great excuse to call up all your friends who graduated last year.
While it may be difficult to locate your old friends after graduation if you have not kept in touch, you can probably still locate them through the Alumni Office. If that fails, try to locate them through their old home address and phone number (Mom and/or Dad). Or send them a letter first class to their old campus address. If it is within one year and they gave the post office their forwarding address, your letter will reach them via mail forwarding, or it might be returned to you undelivered with their new address stamped on the outside of the envelope.