GMAT Strategy

1) what is a realistic score I should expect?

A: You have not indicated your GMAT prep scores. GMAT prep is a reasonably accurate indicator of your score. You could score around your GMAT prep score +/- 30-50 points

2) if I dont do well, what is the best solution to improve my scores?

A: You have provided any info on your prep, for any one to answer this question.

3) is the og11 the best book out there currently?

A: It is mandatory for the prep. You have other good books too.

Wish you good luck!