Q)How did I find maths of GRE?
Answer) Barrons and Kaplan questions for maths are easy compared to actual GRE. Answering the question correctly in the given time is the key. Try difficult questions that appear in GMAT, it will help improve your time.

Q)How much vocab is sufficient?
Answer) There is no limit. Barrons 3600 words though not sufficient are enough to get 550, provided you can do good in RC (cracking RC is different game).

Q)Are there any softwares that help increase vocab?
Answer) WordWeb as dictionary, Vocabulary Wizard 6.3 (www.google.com)

Q) Any tactics that need special attention to get high score.
Answer) Yes, there is one, try ur best to correct first 10 questions in each section, if you lose first 3/10 in maths, i bet you cant get more than 700/800 in maths. Graph questions account more than other questions, pay special attention to correct them.

Q) Hows BIG Book maths?
Answer) its absurd, has no match with actual difficult questions that appear in the test.

Q) Hows BIG Book english?
Answer) Very helpful to get an idea what verbal section is all about, has some good problems.

Q) Whats Power prep all about?
Answer) Its almost exact intimation of GRE paper. Take the tests offered by power prep when you are done with your

preparation and its like 10 days in your exam.

Q) What else?
Answer) Never lose your nerves in the paper, pay equal attention to all the sections, you never know which section wont count towards your GRE score.