Hi
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:
https://gmatclub.com/forum/570-to-700-my-gmat-journey-133461.htmlI have written a post on how to gmat preparations (this is how i did for both the times i wrote the actual exam)
https://gmatclub.com/forum/how-to-start-gmat-preperations-136048.htmlFor Quant i have written a post on how to improve quant score
https://gmatclub.com/forum/how-to-improve-quant-score-137975.htmlHow 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 is
https://gmatclub.com/forum/viewforumtags.phpFor 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!
https://vimeo.com/user3635135/videosLast but not the least: have a little faith and believe in urself and the target was NEVER far anyways!
Good Luck!