1) Do the Exercise provided in your material: Do promptly your exercises which are in your study materials. They will cover all the aspects of your certification. By doing those exercises repeatedly, you can able to answer many questions by remembering the screen of the exercises. Doing exercises will be more advisable than reading the books alone.
2) Don't memorize T-Codes: There are numerous T-Codes in SAP which is not possible for anyone to memorize. SAP rarely asks question in T-Codes.
3) Try to correlate your knowledge with live scenarios: Now, SAP Germany asking many questions based on the live scenarios. When you undergoing for the training for certification, try to map your knowledge or subject with the live scenario. Many students failed in the examination due to lack of this skill. It is difficult for the beginners to know the live situations. To know the live scenarios you can enroll yourself to any SAP forums and watch others queries and answers from the experts.
4) Believe your study Material: Your study material provided by the SAP is more than enough to clear your SAP Certification exam for any module. Don't spend your money and time in books other than the SAP materials. Because your questions for certification will be asked only from the SAP materials.
5) Don't leave any chapters from your book: You need to study well all the chapters from your book. Because there is no syllabus from SAP Germany to ask questions by chapter wise. They may ask or skip any particular chapter. So, you need to know all the chapters. It is dangerous to skip or omit any chapters from your book.
6) Understand the concepts, not the Menu Path(s): SAP Germany asks question to test your knowledge on the concepts. They never test your memory skill about the menu paths and T-Codes. If you know the concepts very well, you can easily know the menu paths.
7) Stay focused during your course: You may do the certification course through Online training module or Instructor led Training module. The most important thing is you need to be stay focused during the time of your Certification course. This is the key element to achieve your certification. Because the available time is less and things to learn are more.
8) Answer the questions which you know very well: You have 3 hours for the exam. It is more than sufficient. It hardly will take just 2 hours to complete the exam. So, you can leave the questions which you don't know or you have doubts. You can think about those questions during the 3rd hour of the exam. If you start worrying about those questions in the beginning of the exam, it will spoil your chances of clearing the certification. So, start with confidence by attempting the easy and known questions.