If you're talking of e-cigarettes, I tried one the other week and had to have a real smoke after it to rid the taste from my mouth. Vile taste it was.
We have these in, with LOTS of flavours. One thing I've seen people do is to try and draw on it when you haven't given it a second to heat the liquid, that is truly vile and would put you off them forever.
The other is using a liquid with a nicotine rating far below that which your used to (8mg instead of 24mg etc) and then still craving a cigarette.
It's not for everyone, but it's popularity is increasing.