I tried to get a couple of mates into it all a while back didn't really get anywhere but then one of them come to me for advice and since he is doing a lot lot better..

My opinion is they've got to want it, most people say they do but if you don't want it bad enough cold approach is far too scary. Don't feel like people can be 'sold' on the idea unless they know they have an issue and WANT to fix it.