Well, if you have servers that are caring individuals but lack inspiration, then perhaps you can go about it from this angle:
Explain to them that by learning better commumication skills and understanding the needs of the guests more, they will have an easier time doing their job. You can quote me on this, "My job only got easier as I learned how to better communicate with people." If they know that they will be helping themselves as well as others, there is usually a more intrinsic motivation present.
As for smiling, well, if they try it out for a day, I think that they will soon see that smiling is reciprocated. The more they smile, the happier the guests will be and the better the servers will be treated.
As for going the extra mile, if servers know that their tips often are directly affected by their willingness to go the extra mile.
Also, when talking to your servers, do not be condescending. Although this is not always the case, there are many servers in the world who are actually quite intelligent, and they will not listen to someone who thinks they are better than they are simply because they are in charge.
If you have anymore questions let me know, for I would be happy to help you.