Predicting trends is not the hard part really, it is picking the right domain in that trend that will sell. I always try to pick trends since I do not have the funds in the bank to buy top domains all the time, sometimes it pays off and sometimes it doesn't. I do believe that Mobile Payments will be next once Apple show their cards, however picking the right domains in this niche at the minute is a bit tricky outside the no-brainers - MobilePayments.com , MobileWallet.com, Wallet.com etc.. I also think NFC tech will play a big role in our lives in the future. An area where I messed up on was following the 3D trend, although I did sell a few this was my first year in domaining and I just followed the crowd instead of thinking logically and just buying a few on the after market. People who have invested in Cloud domains have done well, I remember Giles Coley telling me that Cloud domains will be big in the future, a year later Apple buys icloud.com and the trend goes crazy. I sold - CloudPatrol.com and CloudTribe.com following this. Just try to keep a calm head and do not drink caffeine before reading up on trends.
Cheers