Step 1: Buy a book.
ETS’s GRE is a wonderful starting point. Barron’s GRE was my reference.
Step 2: Familiarize with the pattern of questions.
Jump into doing sample papers, given in the book. GRE is a 4 hour exam, so don’t time your first attempts. Look at the multiple question sets to get a sense of the pattern.
Step 3: Do the lessons in the book.
There will be an assortment of some standard tips on how to attempt certain types of questions. Skim these.
Step 4: Signup for an online course.
This might look like a bad investment to start with. But, an online course of $100 will save you from doing badly in your GRE first attempt. Most people don’t signup, and then retake GRE (which costs $180!). If you know someone else who’s preparing for GRE, share the membership fee and the password. My website of choice is Magoosh Online Test Prep. It also has a free Android app, and thus everything gets complimented smoothly.
Step 5: Build your vocabulary and writing style.
This is crucial, and is not easy. Remembering the 4000 word meanings is very easy. But knowing where and how they are used, is not. The slow and thorough method is to read as much of literary fiction as possible. But you’d have to settle for reading newspaper. Not Times of India or even The Hindu. Accelerate your pace by reading The New York Times [has the best writers and newstories], The Guardian [has the best interface, and its Android app is gorgeous], The Atlantic, The New Yorker [if you’re feeling fancy]. I took the New York Times subscription. Without the subscription you get to read 10 articles. It costs $1 for the first three months. Cancel your subscription before three months (or keep it!). Reading high quality news pieces and articles is imperative because it prepares you for reading section of TOEFL, analytical writing of GRE and writing section of TOEFL. Read the opinion/analysis sections of various news websites to understand making your points precisely and professionally.
Step 6: Do all the exercises of the book and online course.
You paid for everything, so do every question of the book and online course.
Step 7 [concurrently with steps 5 and 6]: Answer one analytical writing question everyday.
When you take the GRE, the first hour goes in typing two essays. If this section goes badly, whole of your exam will. Look at the ETS’ example of best answers. The longer your essays are, the more mark it gets. But, you’ve 30 minutes for each of the questions, so learn to type while thinking and to type fast. To improve your writing use hemingwayapp.com to write. It improves the writing style, as it points out places where you’re using too many adverbs (which is a bad writing practice).