1. Parents have to stop equating love with giving kids everything they want, or everything they didn't have coming up.
2. Parents have to monitor kids access to all influences. TV, social, music/movies, who they're allowed to befriend, where they are at all times.
3. Parents have to introduce positive pastimes and influences. Direct them to academic teams, not only athletics. Martial arts training for discipline and self defense. Be active in planning their future, not leaving it up to a guidance counselor or coach.
4. Expose them to the world outside their community. Have real social networks beyond school and friends. Church/whatever religion groups, or afterschool groups based on their interests to keep them busy rather than gangs.
5. There's no rule that says your kids have to be cool to be popular. Teach them to make trends rather than follow them.
6. I ain't got no kids so I don't know if any of this works (but I was once a kid and this was my family's mantra)