Make sure that you take your time when answering the exam questions, since all of them are scored in full. That means that one incorrect answer for a multiple-response question will cause the entire question to be marked as not answered correctly, thus no points will be scored on the question at hand. Also, you should know that the exam pass/fail grade is not dependent on the number of correct answers, but is designed to give a score out of 1,000. The questions are considered to be of different levels of difficulty and, due to this, each question carries a different number of points that can be scored.
The scoring
The passing score
The passing score itself is never released publicly and the only reference to the passing score is the community of test takers that have posted their pass/fail scores on various forums. The official stance of AWS is that the certification passing score is heavily dependent on the statistical analysis of multiple metrics that AWS receives from several sources. It is widely known that one of the initial sources for determining a passing score are existing AWS certified individuals who have access to technical previews and take the beta exams. The beta exams also determine which types of questions will be included in the final exam and the weight the questions will have. According to the results received from the beta, an initial pass level of the exam is usually selected by AWS.
The initial passing score for all AWS exams has historically been set as a wide range between 650 and 750 points out of a possible 1,000. The initial passing score has been heavily dependent on the type and difficulty of the exam itself; associate exams usually have a higher initial passing score, as the questions in the exam are considered to be less difficult than questions at the professional exam level. Upon release of the exam, the metrics received from the exam takers are also taken into account and the passing score of a particular AWS exam is adjusted periodically based on the live metrics from the exam takers. There have been reports of the passing score being even higher, so you should be aiming to prepare yourself to a confidence level that should ensure that you can answer at least 80% of the questions correctly.