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
How to start GMAT preparations?
How to Improve Quant Score?
gmatclub topic tags
Check out my GMAT debrief
Thursdays with Ron link
Looking for a Quant tutor? Check out my post for the same!
Combined Formula Sheet :
Number Properties || Word Problems and PnC || Equations, Inequalities || Geometry
How to Solve :
Statistics || Reflection of a line || Remainder Problems