I fully agree that one neighborhood has to be tackled at a time. RESIDENT homeowners, who are willing to stay and help the rebirth of their neighborhood should be given incentives. Maybe a grant to get their house sided... a delivery of flowers to be planted on their lawn... New cement sidewalks... etc. etc. This makes the home much more comfortable and the homeowner can take pride in where they live.
Absentee landlords have to maintain landlord/tenant/neighborhood relationships to be able to continue to rent out their houses. They too must be willing to fix up their properties to suit the newer, higher standard of the neighborhood. If not, move on buddy.
Media definitely needs to be involved. Residents never want to be seen as being unsupportive, neither do local businesses.
Neighborhood stores which are prime hangouts for many of the area gangs have to be cleaned up or closed up.
Lots need to be turned into playgrounds where our kids can play basketball and baseball, swing on the swings or cool down in a sprinkler. I'm sick of basketball hoops in the street, but I feel sorry for the kids who have no place to go. Even with indoor gymnasiums available at community centers, kids do NOT want to be indoors during the summer any more than they have to be.
There's so much that can be done with the right people getting this organized and the right people putting the pieces together. The rest will eventually fill in, especially with the media hovering
There are alot of good suggestions here. With the right amount of people with the right kinds of attitudes, the options are unlimited.