There are few things to do before you take the test next time :
Only apply for the test when you think you are well prepared it's not about taking it two or three time it's all about taking your best shot.
Just concentrate and think for a moment what field you are best at and turn it even more stronger like verbal section for example.
Try not to attempt all the questions and do only those questions first which you are sure of being correct.
40 right questions can get you good enough score though there is no maximum limit it totally depends on time and you speed and ability how fast you solve them.
Most importantly Just be confident
All the Best
Shivam Kumar->www.Brainlubricator.com