First off, abuse or addiction all about the Will of the brain. So the first step to help someone with addiction problems is to get them willing. Like one of the drug addiction myth says,
"You can’t force someone into treatment; they have to want help"
To make someone with addiction to want help, you must stair up his or her brain to worry...
Legal troubles, with addiction problems.
Lack of peace of mind in social interaction.
Poor relationship, fights and insecurity.
One addiction will lead to the other, which defines nothing good to the individual, his family and career.
Lack of creative thinking ability as the individual's past.
And lastly, showing your disapproval whenever something became wrong as a result of addiction.
Moderate your criticism, for it might help and can also push the individual into more addiction problem because of the stress you're imposing.
When the individual with addiction problem is willing to change...
You have to first consider dedicating much time to help your fellow.
Talk with him or her about the disadvantages and bad emotions that makes it hard for them to cope without drugs.
Make them agree to be submissive, at least if they want to change.
Be a short term life coach, always guiding and giving them alternatives, instead of drug, alcohol or other addictions.
Most people with addiction problems seek pleasure and happiness, which makes it more harder to overcome.
In this case, teach them to understand and practicalize with them, other ways to be happy apart from addiction.
You just have to take good care of someone with addiction problem in order to succeed.
Dedicate your time and be willing to accept challenges. Be patient but never ever allow yourself to fall into same trap of addiction regardless the pressure.
Do not hide drugs or drinks. Helping someone with drug addiction is a matter of taking him away from it, and not taking it away from him.
If it can be out of reach in a general sense, you should make sure that you do everything according to the person's will.
For example, you might suggest a vacation where you're sure there are no drugs, then agree with the individual not to bring any with him.
On the vacation, although the individual may wish to have take someone, since it's addiction, but realizing He can't find one and He willingly accept the situation in the first place, the mind will settle for this.
Compliment the individual on progress. Encourage and support. Do not nag or show insecurity after you're back.
If He's your loved one, you should be more loyal and committed. Show that you're happy for the slight change and you'll do more when the become visibly permanent.