Hitting the wall - Please share your prep experience

My background:

I have a Bachelor Degee in International Business and I need the GMAT to get accepted in University of Mannheim in Germany; this year's threshold is 600 points. GMAT is not as popular in Europe as in the USA, so the thresholds are a bit lower than on the other side of the ocean. However, from Mannheim I will be able to pursue a semester or a year in the USA, so while 600 is enough to get accepted in Mannheim, higher score would allow me to choose a better business school in the USA.

I am a hard-working student: I've lernt German in under two years and passed the TestDaF - a German language test necessary to study in Germany (a German counterpart of English TOEFL). I have TOEFL, too. Now I am starting my first job as a German speaking IT support.

Answering your further questions:


- My GMAT is not booked yet. I plan to take it at the end of April.


- I haven't taken a complete CAT yet. I have taken two Manhattan Quant CATs that are accessible on GMAT Club Tests platform. I found the questions awfully difficult, I think these tests AREN'T designed to be resolved in under 2 mins per question (you get only 700-level problems and I think they are closer to 800 than to 700). At the first take I didin't finish in time and I scored Q45 (av. time per question 2:48). At the second take I finished on time and scored Q26 (the worse ever). The third CAT I took was a mashup described in my first post in this thread (Q 37).

As to IR, I have done a few problems and scored very well. IR is based on reading comprehension, in which my scores are always above 80%.
As to AWA, I have written only one (timed). You can assess it here: my-awa-topic-1-from-12th-review-149734.html. I am rather used to write such stuff, but of course I need to better adjust my writing to GMAT now.


- I've gone through the Manhattan Guides and the GMAT Club Math Book, and more, so I think that I have all the topics covered.


- If I crash, I do only on the 700-level problems. (Well, OK - sometimes I crash on the 600ths or even 500ths, but such mistakes are rather accidential.) Most frequently on Geometry and Statistics. I was chrashing frequently on few more topics, but I picked up a lot using Khan Academy. However, its problems are generally easier than those on the GMAT. So Khan Academy is perfect for understanding the concept, but won't help with timing.