I was using only official guide 13, verbal and quant review. I was very stupid to do all the exercises in those without any studying of the concepts. That is how i wasted my first months. Then I was following some guides that i found on the gmatclub. This was not a structured approach and that is why i failed.
My scores:
GMATprep 1 (4.9.2014): score 320 Q20 V14 - i did it without any studies
GMATprep 2 (19.9.2014): score 420 Q22 V25
Kaplan (17.10.2014): score 490
Veritas (31.10.2014): score 590 Q39 V33
Economist (10.11.2014): score 460 Q32 V23
Manhattan (15.11.2014): score 500 Q39 V20 - i left the last 15 questions on the test not answered because my computer crashed.
GMATprep 1 (18.11.2014): score 460 Q36 V21
GMATprep 2 (22.11.2014) score 530 Q32 V30
Manhattan (26.11.2014): score 580 Q37 V32
My test was scheduled on 5.12.2014.
Most of the time i took everything but the essay
I study from Monday to Sunday with Sundays off. For the last month i was studying from 08:00 until 18:00 with one hour break. I did not use a structured approach and quality study sources and that is why I failed.