I am a little skinny with a very fast metabolism and I've passed drug test 2 after smoking on several occasions while the Internet says it take a month. How is this possible?! (btw I'm a chronic smoker I smoke a gram of gank virtually everyday. Often times much more than a gram)
It takes at least 3 weeks or so, and that's if you're not too heavy a smoker. Only suggestion I can make is to exercise and drink lots of water. It'll speed up the process, but not a ton. Mostly you just have to wait it out.