Set your team.
Get concerned people around who will help. Each person has to be willing to look the addict in the eye and say, "You have a problem, and you need help." If one person feels uncomfortable about that, you've got a weak link who should not be involved in the process.
Confront factually, but with love, care and concern.
Bring a written list of data to the intervention that describes in detail the evidence that your loved one is using drugs. Confront him/her with content, not argument.
Remember that you are talking to the drugs, not the person.
Any time someone is addicted to drugs, the substance takes over their reasoning and problem solving, and creates all types of paranoia and anger.
Create a crisis for the troubled person.
Remember that arguments are a comfort zone for a person on drugs because it allows him/her to stay in denial. Bring it to a head by giving him/her a choice to get treatment, or face the undesirable alternative, such as jail, getting kicked out of the house, having no contact with family, etc.
Focus only on chemically-related issues.
Keep it focused on the fact that the addict has a disease for which he/she needs professional help. Be specific about when, where and with whom a chemically-related incident happened. Stay on point without emotions or distractions. It's not about yelling, screaming or your opinions. It's about facts.
Get a commitment to go to treatment or be prepared to break contact.
You have to be prepared for the hard decision of letting that person go if treatment is refused. It doesn't just affect the addict, it takes a toll on the entire family.
Have a firm, immediate plan.
You don't want to waste time after you get a commitment. If the person agrees to get help, have a treatment center set up to admit him/her immediately. If the person does not agree to get treatment, know in advance how you will respond.