I used to be good at this. But that was because I was a pretty extreme person living a pretty extreme lifestyle. Staying up till 3am chainsmoking and talking about predestination or quitting pot was pretty normal.
Now I don't know how to do it anymore, because I have no experience at ministering to converts from extreme lifestyles without being right alongside them.
Phonecalls is part of the answer. You can't expect them to keep a regular commitment. They may be in Perth next week and kicked out of their flat tomorrow and back on smack by Thursday and going to a pentecostal church for a month.
But a regular phonecall is achievable, it keeps you in touch and if it is regular and spiritually profound it can be enough. I intend to be more consistent with phonecalling any extreme contacts and converts we are given.