Marion, IMHO there are some tunes in 3/4 time that are best played as airs, not waltzes. Ashokan Farewell is one of them. I like to play this piece a little more slowly and expressivly than what local dancers feel is optimum waltz tempo. For a tune to be a good waltz candidate, I like a melody where the accents are either ONE, two, three, ONE, two, three: or one, two THREE, one, two, THREE. A good example is Tombigbee. Another good example is a waltz I learned from Arkansas fiddler DeAnn Gillispie called Polly's Waltz. It has a ONE, two, three, ONE, two, three feel to it. Another waltz that has the same kind of feel to it is Southwind, another one of my favorites.