No matter how much you study before taking the Praxis Core, that knowledge will be hazy unless you're also in good physical and emotional test-taking condition. Keep the following points in mind in the days leading up to and on the day of the test.
Be sure to eat something before the test, no matter how nervous you are. Even if you don't feel hungry before the test, hunger pangs have a way of sneaking up on you the moment the test starts. If you're too jittery to choke down your customary bacon and eggs, have some bananas on hand, as they make for a good, filling breakfast that's easy on a nervous stomach. And during the test, they'll keep your blood sugar from dropping, so you'll stay alert.
The answer to the oft-asked question "coffee or no coffee" is "do whatever you normally do." If you're a coffee-drinker every other morning, there's no need to go without your java on test day. But if you don't typically drink coffee, suddenly pounding one before the test is more likely to shake you up than improve your performance.
"Get a good night's sleep" is always good advice, but it's important not to psych yourself out by feeling compelled to alter your sleep schedule. If you normally go to bed at 11, the only thing crawling into bed at 8 will accomplish is you getting angry at yourself for not falling asleep fast enough. Once again, "do what you normally do" is the best advice.
Remember that, unlike on some other standardized tests, there's no penalty for a wrong guess on the Praxis, so there's never any reason to leave a question blank.
When a question gives you trouble, eliminating wrong answer choices one by one is more productive than hoping that the right answer will jump out at you.