You could always use cincy boyz technique and somke the day before. Or if you want to do it the old fashion way there a several different factors that come in to play like how much weed do you mostly smoke for how long of a time period the quality of the weed and your body fat level these are just a few that I can think of. A way that I used to do it was to drink vinager which taste like complete ****. Cranberry jucie will also speed of the flushing of your system and taste a lot better. I was and am a pretty hevey smoker and I pissed clean 2 weeks latter but if I were you I would try cincy's technique.