If You Have a Well to Wish In
There are two ways to celebrate Wishing Well Day.
1) You can toss a coin into a well and make a wish. The well need not be one that is specifically designated as a "wishing well". It can be a "well" in a mall, a real water well with a pump or a bucket, an oil well, or any other type of well.
2) You can request that good health be bestowed upon the person of your choosing. You can wish them well.
Neither option is preferred over the other. You can do both methods if the opportunity arises.
The only qualification on method #2 is that you have to really mean it. Just saying, "How ya doing?" as a greeting doesn't cut it. After all, most people who ask that really don't care how you are. If you simply answer that question when they ask, most of the time they don't know how to respond.
They probably didn't even realize they asked the question in the first place.
Merry Christmas. How's it going?