The usual mistake people do is to keep on practicing, without analysing the errors / mistakes. So everytime you practice, you get similar or little better results.
As you have already attempted so many tests, spend a full day analysing the problem areas, and prepare an
error log. You would be surprised to see that generally repeated mistakes are done in few areas. E.g. in my case in Quant it was co-ordinate geometry, probability etc, and in SC it was idioms, verb form etc. Additionally my biggest problem area was reading speed in RCs.
So, do a thorough analysis, and the next 2 weeks spend your time targeting the top problematic areas. Keep attempting
GMATPrep tests to see if you are improving.
now my score has improved in verbal ....i am thinking too much and marking wrong answers even though my mind points me the right answer. In the recent test that i took , switch 4 out of 7 wrong SCs from right to wrong answers..................................English needs to be taught with proper grammer in our indian schools....although i hail from the famous don bosco group of schools, i see no difference when it comes to grammar....