Welcome to the site, snizami!
I think a little more information about the class, where you are in the class and what you are teaching (ESL or EFL) would be useful. Without that information all I can offer is something I posted in a
similar thread:
What have been your goals for the class? Has it been to improve their comfort level speaking? Has it been to improve pronunciation? Has it been to write better? Or do you teach everything in class (ie. listening reading, writing, speaking)?
After you know the goals of your class, then you will be able to grade them on those criteria:
Pronunciation: 1 - 10
Confidence: 1 - 10
etc...
It can also be helpful for you and confident booster for them if you test them at the beginning of the term and then halfway through and then at the end. Therefore they will see improvement, you will see areas that need improvement and in the end they will actually feel like they were successful.
I hope that helps,
Eric