I enjoyed this post from Trulia, you can read the full article here.

Summary:

1. On-trend businesses are moving in (ie: Whole Foods, big banks)
2. Convenient location (ie: transportation)
3. Downsides have an expiration date (ie: crime is declining)
4. Architectural themes (ie: brownstones)
5. Major economic development is brewing (ie: Barclays Center, Brooklyn Navy Yard revitalization)
6. Fixing is in the air (rundown homes being rehabbed)
7. Steady decrease in Days on the Market