The first thing I would advise is that applicants should devote enough time and prepare well in advance. I spoke to many applicants and most of them gave me the same suggestion. All of them talked about the fact that performance was affected when they had started their preparations late.
Secondly, do not underestimate the GMAT. Even though the concepts tested in the GMAT are not very difficult, they require practice. So prepare well and practice enough to be able to get the score you need.
Finally, it is important to take the help of experts. I was very ably guided by Reussir le GMAT and Dr Hubert Silly from MBA Center and I am very grateful to them for their patience and guidance.