I've always had trouble sleeping after gigs (even tho I don't do that as much these days)...it's the wired feeling one gets from adrenaline IMO and I don't think there's anyway to hasten the process up (for me anyway).
I do find tho that I tend to go to sleep *easier* these days - being a non drinker and smoker - than in all the years before.
I usually just lie down and read and, sooner or later, it does the trick
D