one grand gesture
One of the most underused and undervalued tools in a leader's toolkit is the element of surprise. It is fun, really; you can lie in wait in your office with the lights out, and when someone walks in, yell, "BOO!" All kidding aside, the idea of surprise can often be used not just as a culture builder but as a robust tool for building unique and effective relationships inside and outside your organization.
You get the idea.
The concept is simple: by making a single effort towards appreciating those who make your organization possible, you are not just building toward the positive but setting a standard for yourself.
Try it, and see what happens.
Caveat 1: not all of your employees will appreciate it; people be like that
Caveat 2: not all of your clients will appreciate it; people be like that
Caveat 3: it does not matter how it is received; what does matter is that it begins to foster in you and your leaders a desire to appreciate others