This guide assumes that you have a year or more before you're planning to take the test. If your GRE is scheduled for next month, then a lot of what I say here will not be possible for you. Still, this guide will help you boost your scores, so take a look anyway.
Your college experience should include a decent amount of quantitative coursework. Take at least a few math courses and preferably also some science or economics courses. You need to practice your quantitative thinking throughout your time in college.
More importantly, work as a math tutor! College math tutors generally spend most of their time helping students with low-level courses such as finite math. These courses have exactly the kinds of math problems that you will need to be fluent with. I worked about 10 hours a week as a college math tutor for 5 years before taking the test. I got so used to working quickly on low-level math problems that the GRE quantitative was just like another day at work. Your college probably has a tutoring center of some sort. Get yourself hired there as a math tutor ASAP. Try to tutor your college's finite or discrete math courses as much as possible, because those will have problems most similar to the ones on the GRE. You should tutor a variety of math classes, though; it will all help. As an added bonus, you'll be getting paid for all this GRE studying!
Finally, when testing time rolls around, you'll be very well prepared but maybe not quite prepared enough to get a perfect score. The writers of the math questions will try to trick you, and to be safe you should know ahead of time what tricks you might fall for. About two weeks before your test is scheduled, purchase a couple GRE quantitative review books and only work the advanced-level questions. You will probably make a few mistakes and miss a few questions. (Be careful, though, because some of these books are very low-quality and have a lot of wrong answers themselves - check amazon reviews before making any purchases!) Circle the questions that you miss and rework them a few times the day before the test.
Note that you can miss quantitative questions and still get an 800. This is important to remember when taking the test. You will need to work quickly to finish all the problems; I finished with only a few seconds left. If you come to a question that really stumps you, don't waste a bunch of time on it. Just answer with your best guess and keep moving. You can still get an 800 if you're wrong about that one.
If you're a native English speaker and you're at a stage in life where you're about to take the GRE, then you've probably developed a pretty solid vocabulary by now. That's good. But it's not nearly good enough to get an 800. Hopefully you studied vocabulary words for the SAT, because that will help provide a good word base for you.
About three months before the test, you need to begin the process of learning thousands of vocabulary words. Purchase one or more comprehensive GRE vocabulary word books. The first thing you should do is remove all the words that you already know. Go through each book word by word. Cover up the definition and see if you can define the word. If you can define it at this point, then you will probably be able to define it on the GRE in three months. You don't need to study it; it is only cluttering your prep material. Mark it out with a black marker. After you have done this with all your word lists, you should be left with a ton of unmarked words that you need to learn before the test. Break these up into groups of about a hundred words. Learn one group at a time. For me, the best way to learn is to be quizzed. I made my girlfriend quiz me once a day. (If you don't have anyone who will quiz you, you can quiz yourself.) On the first day of quizzing, if I could easily define a word that she asked me, she would leave it unmarked. Otherwise, she would highlight it in yellow. The next day, she would only ask me the yellow words. If I knew a word, she would leave it yellow. Otherwise she would highlight it in orange. The next day, she only asked the orange words. And so on. Once that process ended, she would go over all of the words in the group to make sure I could still remember them all. Then we would move on to the next group.
Really, you should immerse yourself in vocabulary practice and try all sorts of ways of learning words over this three-month period. Get some funny or interesting vocabulary books to read. Get some vocabulary workbooks to work through. Just make sure the materials are advanced enough for you. Listen to vocabulary podcasts when you're in transit or working out. Check out other interactive web resources such as my GRE vocab practice game for learning vocabulary, too. (I made the podcast and the web app linked above, so you know they're good.)
Finally, during the two weeks preceding your test date, do a lot of vocabulary practice GRE questions from a prep book. Just knowing the words isn't quite enough. You've got to be able to identify analogies and antonyms, so you'll need some practice.
Unfortunately, not all of the verbal questions are vocabulary-based. You will see a good number of reading comprehension questions as well. These are not easy to prepare for. You should go through lots of practice reading comprehension sections from test prep books in the two weeks leading up to the test so that you can get an idea of the types of questions that will be asked. Your main strategy for this section is to take your time. You will be so good with vocabulary that you will answer all of those questions in no time. That should leave you plenty of time to read and think carefully on these reading comprehension problems; I finished the verbal section with over 10 minutes left.
Oh yeah, there's a third section. I don't have much to say about this one. If you're a good writer you'll do well, and if you aren't then you won't. I guess you should try to take a few writing courses to keep yourself in practice. Check out a GRE review book, and look at example questions and responses to see what is going to be expected of you. Note the different expectations of the two different essay sections. Also, note the tips listed in the review books, such as writing as much as possible. Just do your best on this section; it's not easy to prepare for.
Technically this guide is about getting a 1600, which has nothing to do with your writing score. I only got a 5.5 out of 6 on this section, but I still get to brag that I "scored a 1600."
- take a good number of quantitative courses
- work as a math tutor for as long as possible
- go through advanced-level practice problems and circle your mistakes
- on the test, work quickly and guess when necessary
- spend three months learning as many vocabulary words as possible (thousands)
- work through practice sections in the two weeks before the test
- on the test, take your time on the reading comprehension sections
- take a few courses that require writing
- read tips and examples in a GRE prep book
Take the GRE at the very end of the last summer before your graduate school applications are due. Spend the entire summer gradually learning tons of GRE words and the last couple weeks doing practice problems.
Following this guide cannot, of course, guarantee that you will score a 1600, but it will give you a very good chance. And even if you don't get the perfect score, I bet you will get pretty close.