Having recently gone through the process I complete agree. It s all about preparation. Remember that the tests are conducted against the clock and there is insuficient time to complete all the answers. It follows that those that have prepared will complete more answers in the time allowed. A trip to your local library will reveal a few books on the subject. Do some of the sample tests and time yourself. You will be amazed how quickly you will improve wit a bit of practice.
I found reading about interview techniques also quite useful. Although in the end you have to be yourself, it helps to understand the point of view of the interviewer and to anticipate some of the questions. I found plenty of books also in my local library.
The 5 P's. Prior Preparation Prevents Poor Performance. Isn't this what in the end the job is about? anticipating what is coming and preparing for it?