The measure of success is not whether you have a tough problem to deal with, but whether it's the same problem you had last year.
—John Foster Dulles
The 70-442 exam focuses heavily on coding using Transact-SQL. If you start off as an expert in T-SQL, you're ahead of the game, but don't skip Chapter 4. You'll find that some of the new T-SQL features will definitely be on the exam. Additionally, any T-SQL programmer should know how to create, implement, and troubleshoot stored procedures, so you're bound to see these topics on the exam.
You can also expect some advanced developer concepts to appear, ...