The first 10 usually are the easiest, so I always try to finish them within 10 minutes. I try to get to number 20 by the 23rd minute. That leaves me with plenty of time for the final 5-7 questions, which are always the hardest for me. And it gives me a minute or two to review the hardest questions. If I'm even slightly unsure of a question, I place a big question mark next to it after choosing my answer. I use those final minutes to review the flagged questions, and whenever I change my answer, it ends up helping my score.