Hi! I would suggest you two things-

1. CMAT has some really tough GK questions, other sections are pretty much easy. Moreover, it has both static GK and current affairs questions. So, read monthly current affair magazines and prepare for static part topic wise.

2. Buy 1-2 test series specifically for CMAT. I had bought IMS and TIME, though I could utilise only IMS. According to my experience, practice is the only key to excel in CMAT.

All the best!