How do you encourage growth in a decaying region?
Why are there so many empty lots?
How do you create a business when no one can afford the land?
In an area of significant decay where the lot sizes are uniform; I propose breaking up the lots to allow smaller, cheaper development. Small developments are by nature highly dependent on outside support, and as they grow they build networks. When a local network of small businesses reaches a critical mass the area will begin to grow compete with its neighbors.
Current building codes restrict development to a single type which is out of reach for most in this area.
When several people are allowed to share a lot, the can pool their resources and create something.
Remove lot, zone and density restrictions, and allow new development to build off from what already exists.
Sharing infrastructure can reduce some development costs; this can bring the opportunity to start a new business within reach of low income groups.
A critical mass of small developments can bring new life to a once decaying area.