Is there anything that I can do while waiting for the decision on scholarship
The period between admissions and scholarship decisions is not really any different from the period between submission and acceptance notification.

If you have any major changes in your status—if you receive a significant award ("Best paper," teaching award, or similar), or if you have made a notable research contribution (published a paper, or at least submitted one), then that would be relevant information for the department. Otherwise, you'll just have to bide your time.