Get there early - familiarize yourself with locations and environments
Breathe deeply - lowering your stress level helps you perform better
Don't expect to know everything - it's unlikely that anyone will answer all questions correctly
Preview the exam - read the directions, note the number of questions
Start with the questions you know - build confidence and time for the harder ones, don't get stuck on the ones you don't know, flag them and come back to them at end.
Plan your time and pace yourself - aim for an average of 1 minute per answered question
Allocate time for review - on second reading, your answer may change
Read each question carefully - have it clear in your head before answering
Read each answer - note all those that are wrong
Choose the best answer - or make an educated guess if you aren't certain