I have reduced my Cannabis use over a period of 2-3 years, from twenty or more 'single paperies' per day to one or two late in the evening.
The biggest factor was eliminating tobacco from the equation, I mixed the pot with a variety of kitchen herbs with very limited satisfaction for a couple of years, eventually the tobacco craving subsided and I no longer felt the need to smoke a little joint every hour or so.
I couldn't find many herbs that didn't have my friends asking me if I was smoking the Sunday roast, the most unobtrusive herb I could come up with was Sage intended as a Tea.
Recently I discovered Damiana and I haven't looked back. I would describe it as a "Stone Enhancer", it definitely gave me a very cruisey, laid back stone and put all in the world right again. It was discarded by a friend and given to me in plain packaging. I had no idea it was supposed to by an aphrodisiac or mood altering drug so I was very pleasantly surprised when the effect kicked in.
It was a very subtle effect and probably not noticeable to someone who is habitually smashed on weed, but in my low-intake state it definitely had me feeling very happy with life and my lot in it. I don't attribute this happy state to the pot because I smoke to wind down, veg out a bit before trying to go to sleep at night, it doesn't usually make me happy, just switches me down a few notches.
Another feature of this herb is that it has the same pleasant raspy-ness that satisfies tobacco smokers. Most other herbs don't seem to offer this; they are either too smooth or too harsh.
I would highly recommend at least trying it to see how you go. The price is a bit scary though, compared to the ten dollars a half kilo that my friend paid from a wholesaler somewhere.
Cheers and good luck.