When my daughters took the SCAT tests last year, and it was their first time ever taking a computerized test, I just had them do the sample problems that was in the CTY booklet we received. There were only 4-5 problems for each levels, but it showed the screen view, which I thought was important so they were familiar. I also got them an analogies workbook to review some basic concepts, since I wasn't sure if they were familiar with analogies.
Mainly, just be sure to get good night sleep! For my "speedy" daughter, I reminded her to check her work if she was done early. For my other daughter, I reminded her of the clock time at the bottom of the screen so she can pace herself.
They thought the tests were fun.
