I haven't had to to it long haul for a while now (and short haul I don't care - if I fall asleep naturally great, not that bothered if not).
But when last I did on a regular basis I found a method that worked for me;
1) Optimal amount of food and drink. Definitely a couple of glasses of red, but try and avoid too much more than that.
2) Optimal clothing. Light layers and nothing too difficult to add / remove so that the amount you wake yourself if you need to tweak it mid flight is minimised
3) Use the blanket or a hooded sweatshirt to completely cover the head. If a hoody, use the drawstring too.
4) Inside this little cocoon I have my ipod, with in ear buds (in lieu of ear plugs) and a selected quiet playlist. I find this better than no sound.
I didn't always get fully asleep that way, but I did find that it allowed my mind to disengage and at least get to that half sleeping state pretty consistently.
But it's a totally personal approach.
My $0.02