And it's borderline candidates who are going to receive closest scrutiny and that means a close look at GRE Writing Assessment scores. DO take practice tests with the goal of building up endurance. DO take the real GRE once just for practice as a dress rehearsal if possible. If you have time and can afford it, you should register for and take the real GRE once as a dress rehearsal just to get comfortable with the testing environment. DO take the GRE early to allow yourself the option of retaking it.
Most graduate schools admit new students for the fall term only.
Although application deadlines vary widely among the schools, if you plan to take the GRE no later than December 15th prior to matriculation, you'll be sure to meet any school's application deadline. Ideally, you should take the GRE early enough so that you can take the exam a second time if necessary and still meet application deadlines. In any event, take the GRE at a time when you're not distracted by other pressures at your workplace or at school. The intellectual abilities measured by the GRE are developed to a great extent during your four years of college. So if you're still in school, wait at least until the late in your junior year to allow for further intellectual development and higher GRE scores.