Thorough familiarity with the Integration Server Built-In Services Guide is critical to success in working with IS. While you’re at it, study the Developer User’s Guide, the Java API javadocs and the user’s guides for any adapters (JDBC adapter especially).
Of course, diligent study and practice to develop expertise with XML schema and SQL would not be wasted effort either.
Both are equally important IS topics Broker (Pub/Sub) and TN processing,you got to review both tutorials not only for certification point of view also theory/practical hands on (preferred).