Hi guys,
First, I want to say thank you to this wonderful website and all counselors from the different prep companies, I couldn't have done it without it/them.
Second, it's not going to be a very long post: I just want to persuade people that perseverance is the key to success.
My first GMAT exam was interrupted by a fire alarm in the middle of the quant section, so I finished up with a 680 (pretty good but below the "700 barrier").
I decided to re-take the exam 3 months later, and the second time everything became clearer.
Here are my tips:
1. Everyone has his own pace, don't search for a magic number for the hours to spend on the exam (I'm almost 39 years old, married + 2 and I'm sure there are faster dudes than me

)
2. Persevere even when you're tired/your kids drive you crazy/the boss is angry on your deadline/your wife wants a date.
3. Persevere a little more, never give up!
4. Read a lot: books, magazines, listen to lyrics, correct your colleagues in English at work (I'm not a native speaker).
5. Make calculations about everything: at the groceries store, calculate your fuel consumption, the fee of your mortgage. It's very good for practice!
6. Believe in yourself! Learn 200, 300, 900 hours, that doesn't matter! Just learn and believe!
7. Register for the exam and make your plan backward according to your schedule.
That's it,
Good luck!