Hello trishna26,
I have also found the these practice CATs (Kaplan and MGMAT) tougher than the actual. To get a feel of where you stand you should try out GMAT Prep (from MBA.com). They are the closest to the real thing compared to any practice CAT.
I saved my Prep CATs for the end. I'd suggest that you try analyse your tests and figure out where you are going wrong. Try to see how you can improve on these areas. Take the Prep CATs a week before your test and don forget to analyse them thoroughly.
One more piece of advice - when you take these CATs do not skip the AWA essays. They help you prepare for AWA and also help you with the stamina part.
