Not OP, but chewing normal non-nic gum is commonly used as in combination with other quitting methods to help appeal to the physical oral sensations associate with smoking (obviously it's not a perfect proxy, but just "something to do with your mouth).
Ultimately, all cessation methods are aiming to require 0 nicotine at their conclusion. As for the "best thing" to do when trying to quit, financial loss seems to be a good incentive. http://www.nejm.org/doi/full/10.1056/NEJMoa1414293
Would you please do a better job of following the site guidelines? You frequently either cross the line or straddle it. By doing this, you damage the community in its most vulnerable place. I'm sure you wouldn't do that with other shared resources, and since you use HN, we'd appreciate your helping to take care of it as well, even when other comments are annoying, wrong, or absurd. Especially then.
No, I asked: what should vaping be replaced with?