Hi Swati,
Even I feel so tired filling up PMS forms for my team. Shortening the form depends on the type of appraisal method you are using. We have a very simple method, and I will tell you what I did to shorten it.
See if there are any points or attributes that are redundant in your forms under different heads and names. For example, judging a person on time management and attendance/late comings is almost the same thing, so you can delete attendance/late comings.
See if you can change all the attributes and feedback to just a point-wise pattern. For each attribute that you want to measure, you can have points on a scale of 1 to 10 so that the manager doesn't have to write stories.
One more trick I used in my organization which actually worked well was to print the form on both sides of the paper. It makes the form look smaller. But as I said, it depends on the kind of appraisal method you have.
Regards,
Deepthi