as noted by others, quite a few studies have shown that behavioral changes (as opposed to medications, herbal or otherwise) are the most effective way to combat insomnia. there is a great NY times article from a couple of years back that summarizes the studies and tips- you may be able to find it if you search

for me, this is what helps:
-minimize caffeine and no caffeine after 12 noon (one of the most important things for me)
-keep a regular sleep schedule-- to bed and up at approximately the same time. do not sleep in to compensate for sleepless nights
-sleep a little less than you think you need. I love getting 8.5 hours, but find I generally sleep more consistently if I get 8. I know, a lot. I've been this way since I was a kid.
-exercise a lot (probably not an issue for TE readers!)
-do not lie in bed when having trouble sleeping. get up and do something non-stressful (ie, not work). I find that I get sleepy after about 20 mins out of bed. much better than lying in bed trying to relax and sleep
-I catch up on sleep using afternoon naps on the weekend, if I've had a hard week sleepwise
-try to chill out at least 90 mins (preferably more) before going to bed. No work or other stressful or "mind-active" activities.
-when I am very very sleep deprived, I paradoxically have more trouble going to sleep. Under these circumstances, and these only, I might take half an ambien to force some sleep. Otherwise, I find sleep aids, including natural ones such as melatonin, not to help so much. The sleep is not natural sleep, so multiple days of using these things just make me feel worse
-if you have morning wakefulness (as I do-- never any trouble falling asleep, but I wake up in the early am and can't fall back to sleep), make sure your room is very dark- good shades to prevent light entry

other tips in the article that don't work so well for me but might work for you:
-use the bed only for sleeping. do not read, study, watch tv etc in bed. the idea being to make the bed a sleeping only environment. this doesn't seem to help for me
-conversely, sleep only in the bedroom. no falling asleep on the couch in front of tv, then moving to bed, etc.

insomnia is really really awful- good luck sorting this out!