It is often difficult for test-takers to focus on questions and not get distracted by the clock ticking. What you can do is check your progress with every five questions. This way you won't lose concentration. Each question should take you more or less 2 minutes (in the verbal section it is slightly less than 2 min, whereas in the quant section you have a bit more than 2 min per question). Solving 5 questions should take about 10 minutes, which is easy to follow and remember.