I've had this problem. I think the enemy is overthinking. The strategy of the test is important, but always rely on your instincts first and foremost. Strategies should be implemented through habit; you don't ever think about them, except when you're developing the habits. The rest is your natural thinking, plus practice and experience. If you have to, go into every question assuming it will be simple, and give it a shot, because most of them are. Don't be afraid to take a deep breath, or if you have a chance, take a break.
I've had this problem. I think the enemy is overthinking. The strategy of the test is important, but always rely on your instincts first and foremost. Strategies should be implemented through habit; you don't ever think about them, except when you're developing the habits. The rest is your natural thinking, plus practice and experience. If you have to, go into every question assuming it will be simple, and give it a shot, because most of them are. Don't be afraid to take a deep breath, or if you have a chance, take a break.