I Gave My First GMAT last year & scored a meager 590! I Prepared For Another 11 Months And Finally Succeded In Scoring 700 (Q48 V37).
The EmpowerGMAT MBA Course was really Helpful For My Preparation. I Liked The Way It Is Structured, And The Practical Tips And Strategies It Offers. For QUANTs, We Have Test-It & Triage Strategies Which Really Were Helpful During The Exam.
In The VERBAL Section, I Really Liked The CR Box That Has Been Prescribed For CR Accuracy. It Gives A Template To Your Thought Process And Increases The Probability Of Getting The Correct Answer. Similarly, RC And SC Have Helpful Strategies And Courses.
Other Than These Empower GMAT Has Summary PDFs And Tips For Exam Preparation, After Doing A Course Consistently For 5-6 Weeks I Was Confident Enough And Booked My Test Date.
Few other tips
Persevere: if you perform poorly do not blame yourself. Figure out which sections are your strengths and which are your weaknesses. Once you know this as a sculptor polish your strengths, and make your weakness into your strength. I knew I was weak with verbal, esp. CR and SC.
I gave in total 34+ mocks, so by that time I was super used to exam timings, and in fact in my mock just before the exam I finished quants with 15 mins left.
Diligently review your mistakes after each mock, empower GMAT has a mistake tracker you can use.
Keep your eye on the big picture of getting your MBA done, and GMAT is just a stepping stone.