You should plan properly to pass professional certification exams. These exams are very different than university exams. In university exams, you appear in one exam on one day and if there are assignments and projects as well as mid term exams, the importance of final exam goes down significantly.
However, professional certification exams require that you give your best and perform on only one day. This requires organizing your studies in a manner to facilitate review of all notes on one day.
Many students are not able to achieve this objective and find themselves in a problem as the exam day approaches. Many test preparation providers have developed tools and techniques to help students in organizing study material.
One popular tool is to go through practice exams which mimic the actual exam environment and format. Students can learn about their exam preparation by taking these practice exams. Some commercial test preparation providers allow students to compare their performance against other candidates. This can be good or bad.
Some students get so much demotivated after practice exam and that they loose all confidence and are very worried on the exam day. Some students gain confidence from the practice and are better prepared to face the actual exam.