I've never had what I would class as proper insomnia but i've always struggled to switch off and actually get to sleep, for a s long as i can remember.
I've changed my lifestyle quite a bit over the last 2 yrs and sleep fine 99% of the time now.
See if any of this works for you:
Stop smoking, I used to smoke but only when I'd been drinking. used to mess up my sleep for a week!
Exercise, I do some form of exercise about 9 times a week, without feeling 'over-trained' in the OP circumstances, dont go the gym about 7pm, I find draggin my arse out of bed before work has multiple benefits. You will be tired at the end of the day instread of buzzing from evening exercise. Also the early exercise means I feel really set up and ready for the day. The gym is less busy 1st thing and I can get on the stuff that I want. also the mental benefits are huge. I find I can zone out at the gym, If boxing you cant think about ANYTHING else other than the moment your in, when running I stick some tunes on and have an hour or so to get my head in order.
All this leaves me in a position to switch off when i get to bed.
Stop drinking brews after 2pm.
No internet/computers/mobile phone after 10pm
I try and give myself half an hour to read in bed, (get a lamp that wont keep the mrs awake!) reading will also help your mind switch off as your transported into someone elses thoughts.
If I am struggling to sleep, I try to recognise it, switch the lamp on and have a read until I cant keep my eyes open and then try again.
The feeling of frustration at not being able to sleep makes it 1000 times worse when you are just lying there pissed off about not sleeping!
At weekends I try not to break my pattern too much, mega late nights or sleeping in half the day will wreak your sleeping pattern for the coming week.
Best of luck blues!