FD Review is here to help!
It allows you to review each of your tickets and rate the agents that worked on it. You can add notes to each rating to help encourage, guide or teach agents.
You can assign each ticket a difficulty level, so that you can determine which at which level agents are working, and whether they are improving over time.
If more than one agent worked on a ticket, you can rate each of the agents individually.
Agents can also see a dashboard, showing their metrics from inside Freshdesk.