previously i have only very small knowledge on ejb but i have very good exp on hibernate, so hibernate help me understand JPA part very quick & easily
Transactions & Exception handling,Persistence Context propagation all needs to understand in details, here nothing to remember
i think Ejb overview, session bean,message bean & some others chapters is very easy to undestand.
needs to reads & remember some points on security & role-responsibilities(deployer/administrator/Bean Provider etc)-this all are very easy to understand but a little problemetic to remember.
i have done some basic fundamental practice following Mikalai Zaikin (II. Appendices chapters) , its help me to setup development environment very easily & quick , got some practical knowledge of ejb & hence i improve my confident
i follow Enterprise JavaBeans Edition 5 Oreilly's Book to understand overall knowledge of ejb
& study guide made by Mikalai Zaikin for knowing some good points thats helped me for certification exam.
follow ejb specs to understand some chapters in details
have practice some free mock exam.
let me know if i can help you any things else