To be adequately armed for effective contract negotiations or renegotiations, it's imperative that you know your existing contracts inside and out, says Roy Schleiden, senior manager of IT procurement at , a transportation services company in Overland Park, Kan. "It's amazing to me how many people don't read their contracts and don't know what's in them," he says.

2. Give Back Shelfware, and Don't Buy More.

Wang says that many clients overestimate the number of user seats needed for a particular software system and end up licensing a lot of shelfware. "There's a lot of room to cut licenses," he says.

But many licenses are designed to make that difficult to do. If a customer wants to reduce the number of seats, some vendors, including SAP AG and , typically respond by raising the price per seat, says Wang. The net result: You pay the same and get less.

Although both SAP and Oracle tend to be fairly rigid about lowering the number of user seats in software agreements, there are techniques you can use to get around this problem with other vendors.