The thing is that names tend to move in cycles. As popular versions of names wear out, people move on to similar-sounding variants, and those start to trend. So you might be able to get some idea of what names are going to trend by looking at what's trending now.
Then again, sometimes names trend for reasons that you just couldn't have ever predicted. The name of a character on a popular show, a celebrity baby name, etc.
As for my own names: somehow, I feel pretty sure that "Harley" and "Constantine" won't be climbing the charts much any time soon. "Constantine" might get a slight bump from The Hunger Games bringing back classical Greco-Roman names, but it's too "weird" and long to ever be popular in Western English-speaking countries, plus it does not lend itself to nicknames well. "Ivy" did jump all the way from 267 to 187 between 2011 and 2012, so it could be starting to trend as an alternative to some popular flora names (Lily, Violet, Jasmine), but I doubt it will break top 100 anytime soon.