If you would like to thank your staff are doing a great job, here is a sample commendation letter for staff.
Congratulations on your exceptional performance in the past [year/months]!
I hold the pleasure of expressing my gratitude to each of you for all your sincere efforts and exemplary devotion. We take pride in having accomplished yet another milestone all because of your remarkable contribution to [firm]. People are our biggest assets and we must take a moment to reflect on all the hard work behind our accomplishments.
Thank you and keep up the good work!