My core emphasis as a GRE tutor is practicing only on official questions whenever possible. That being said, there is not enough computer-based practice material from ETS, which is where outside tests such as the
GRE Prep Club Tests and Manhattan GRE CATs come in, as well as math review sheets, verbal strategy books, vocabulary mnemonic lists, etc.
At the very least, you should
try all 320 questions from the 2 PowerPrep CATs, the 59 unique questions on the paper-based PDFs, and the approximately 600 paper-based questions in the Official GRE Super Power Pack. That's nearly 1,000 real GRE questions right there. Then, when you're done, repeat the ones you got wrong until you understand them fully. Don't look at the correct answers until you've tried them again, and repeat this cycle until you either understand them fully or have memorized the answers and thus need to try similar questions instead.
For example, when correcting my students' paper tests and practice questions from the Official Guides, I won't read them the correct answers. Instead, I have
them read
their answers to
me, and I either say "yes" or "no." They might know that their answer choice was wrong, but they still won't know the correct answer, which will keep them honest on their second try. Obviously, this type of study works much better with a partner. But good CAT software should have this type of functionality (hide your answer / hide correct answer) built in as well, which allows you to review the question before clicking "show answer." The "Review Mode" of the GRE PowerPrep software does not hide your answer, but it does hide the correct answer so you have a chance to try it again.
Once you know the correct answer to a question, it loses much of its utility, so try get as much learning out of it as you can before that point. Again, avoid the temptation to click the "Correct Answer" button right away; before doing so, try the question once more.
For more information:
GRE Action Plan
22 May 2016, 22:37 
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