This one definitely needs to be taken with a grain of salt, because it is not what would be classified as a behavioral suggestion. I try to limit my intake of stimulants before I take tests. The one time that I was hopped up on caffeine (I mean really jumping) I felt good on the math section, but kept skipping around in the verbal passages. On this one in particular as Akamai would say your mileage may vary. Might have the opposite effect on some people, which is why it's good to know your own response to caffeine intake, nicotine etc. Rarely do such chemicals have no effect.
I also try to delude myself into believing that the material is engrossing by reading the first two sentences of boring passages very actively. The more I comprehend the first paragraph of a passage the more likely I am to enjoy (don't laugh) what I'm reading. If you can make the most boring aspects of the exam interesting it is less likely you will lose focus.