As an observation, there are no lists of complete study guides for the SCJP accreditation exam. Most materials are made just to help an examiner in training and preparation for an actual exam. But such materials still prove to be very helpful when it comes in assisting exam takers, or those who are considering a career in the SCJP field. Spending some time with SCJP books, or even at least one, that tackle SCJP certification (and finding resources that deal with SCJP) are all essential for successfully passing the SCJP exam.
One tip for the SCJP exam is that most questions of Exam 1.4 of SCJP require code based answers. Practicing your coding skills to prepare you for the exam is highly recommended. Be sure to be well informed on topics such as wrapper classes, hashcode methods and collections.
Several aspects of the Java program language are not as commonly used in real life to the extent that they are used in exams. This may confuse you if you are not prepared, so be sure to understand how Java code works, especially the Shift operator.
Another difficult topic is multithreading and it is also there in SCJP 1.4 knowing how to construct a thread using a Java program in different ways. It is also important to have a good understanding of synchronization, and being familiar with the functions in creating multithreaded application is also a plus.
Memorizing the inheritance hierarchy of Exception and Collections Classes may also be useful.
Giving enough attention to the I/O objective is also useful if you are to take an SCJP 1.2 exam. It is suggested you apply various I/O classes and those that are related to File I/O streams.
Being aware of Garbage Collection is also essential. The garbage collector cannot be forced to run, so the answers are not verified easily.