I think it may be easier to create the next wave than to predict it!
YMMV, of course, but I think the best thing to for any artist or photographer is to stay true to themselves. That said, you may not sell anything, so what the heck... jump on the latest trend bandwagon!!
Emerging artist, as other's have said, seems to be those artists that are starting to become more well known, and have sold a few pieces, particularly to known collections or museums. Knowing this, it would seem that I and many others are still buried deep under the dirt!!
The art market is just that... a market. It's fickle, hard to predict, but, I do think it can be mastered. It is, after all, pretty big and diverse. I'm sure there are collectors out there who find conceptual work boring, just as there are collectors who find traditional landscape boring. And plenty who love conceptual, and plenty who love landscape, etc. etc.
Research all the players, and you may find a good fit for your work. Trying to predict the market seems an unproductive route to flourishing in it.
Joerg Colberg's blog, as mentioned above is a good place to start. Participating in portfolio review events can open doors. Google
Lens Culture, and
Flak Photo for online sources to show your work. And, lastly, Mary Virginia Swanson's blog.. Marketing photos is a good blog to keep your eye on for opportunities to show work.
http://marketingphotos.wordpress.com/