Warnings
Don't threaten the dealers. This will bring open hostility into your relationship. Be wary of confronting them rashly; While many can be reasonable people, there is the distinct possibility this will be a very dangerous course of action. If you decide to take this risk, be strong but reasonable and as friendly as possible. Do not threaten to call the police, and try to relate to them without appearing condescending.
Be careful! Some drug dealers are dangerous people! Know when to keep quiet. You don't want to get yourself or your family hurt.
Take notice of your surroundings. People with drugs on them are unlikely to cause a scene in a public area, so confront them in areas with people around.
“Business Alert” does more than just ally against drug dealers: all quality of life crimes are reduced when businesses are vigilant and do not compromise their stance. Take pictures of the actors (surreptitiously of course), the drug paraphernalia left behind, license plates of cars if you can. Hard evidence helps the police do their job.
Children require alternatives to drugs, so work with your community to ensure quality options to street life.