First thing: People do screw up in the first GMAT exam so don't panic... take it as a learning and prepare harder for the next exam!
I got a 570 in my first gmat when i scoring 720+ in my mock tests! Check out my Debrief:http://gmatclub.com/forum/570-to-700-my-gmat-journey-133461.html
I have written a post on how to gmat preparations (this is how i did for both the times i wrote the actual exam)http://gmatclub.com/forum/how-to-start-gmat-preperations-136048.html
For Quant i have written a post on how to improve quant scorehttp://gmatclub.com/forum/how-to-improve-quant-score-137975.html
How about making a progress chart or error log
? I talk about that in how to gmat preparations link shared above.
For practice try grockit.com (its questions are timed... just give it a try and you will know how good it is!)
Also, try gmatclub questions.. gmatclub tag link ishttp://gmatclub.com/forum/viewforumtags.php
For Verbal.. can you be more specific where you screwed up? I screwed up in SC and RC i guess and i tried Thursdays with Ron and it helped me a lot!http://vimeo.com/user3635135/videos
Last but not the least: have a little faith and believe in urself and the target was NEVER far anyways!
You must Believe
GMAT Quant Tutor
How to start GMAT preparations?
How to Improve Quant Score?
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Check out my GMAT debrief
Quant Formula Sheet
How to Solve :
Statistics || Reflection of a line || Remainder Problems || Inequalities