If you’ve made it this far, congratulations. You’ve taken a huge step toward better understanding and successfully negotiating the contracts that govern your Agency’s work. Even when you can’t get the wording you want; at a minimum you’ll have a better understanding of the risks your Agency faces so you can make informed decisions. Ready for more? These other resources are a great place to start.
Go get Design is a Job by Mike Monteiro and read it. Done? Good. Read it again. When you are done, check out Mike’s 2011 talk at CreativeMornings in San Francisco, F•ck You, Pay Me. The lawyer Mike talks with in that video is Matchstick's very own Gabe Levine. These resources are simply great. Not just for what Mike says about contracts (nearly all of which I agree with wholeheartedly), but for what he says about communicating with clients. If you understand what Mike says, you’ll be in a much better position to negotiate agreements and deal with projects that come up during the project.
Mike talks a lot about communication. Communicating well is good business and good legal protection. Communicating well will do more to manage risk than the best contract. One of the biggest mistakes I see is people trying to use a contract as a substitute for communication. It should be the opposite. A contract should be a catalyst for and documentation of communication with your Client.
I also strongly recommend any of the content produced by the Bureau of Digital. Attend one of their Camps or Summits. Get involved in the communities they maintain. They are full of people that work in, on, and with creative agencies of all types. It’s a tremendously supportive community and amazing resource.
Last, you might want to check out the AIGA’s book Professional Practices in Graphic Design or AIGA’s Standard form of Agreement for Design Services. The Standard Agreement is an updated version of the contract included in the Professional Practices book. While I’m not crazy about AIGA’s standard form of agreement as a piece of writing or as an agreement for most creative firms to adopt as their own due to its length, language, and point of view that doesn't reflect a reasonable approach to certain of these issues, the concepts covered in the agreement and the associated discussion are valuable resources.