Follow grammar rules not your ear when it comes to SC

The e-gmat verbal tutorials are excellent for non-native English speakers like me. The tutorials explain concepts in a simple and easy to grasp manner. For sentence correction I used to go with my ear i.e how the sentence would sound to me and would hover around the 94 percentile but e-gmat helped push my score to 99 percentile. The tutorial on Verb-ed and Verb-ing helped me especially as verbs were my Waterloo.
I stopped following my ear and strictly applied the grammar rules and lo and behold my score increased drastically. I feel e-gmat's sentence correction is very helpful especially for non-natives because the English we speak is very different from gmat English.