I've been on those horrible long haul flights before, and often ones with lame connections (like having to wait 9-10 hours for my connecting flight!)
Some tips I would offer for you are...
Sleep...as much as you can. I haven't found anything that make the time pass faster than sleeping, but I am also one of those people that finds it hard to sleep on planes.
Books. Lots of them. These days with kindles and being able to load up books electronically, we're spoiled for choice! I usually have a number of books loaded on, in a number of different genres -- you can even get travel books so you can read up about your destination!
Puzzles/crosswords - something for the brain!
Snacks - eating passes time!!
Music - if you have something to listen to that can also be fun...and not just music, but podcasts are great too for something different!
Watching inflight movies or even bringing your own device (iPad for instance) with other movies loaded on.
Sometimes I've even managed to pass time by chatting to the person next to me, but I would be careful with that - not everyone wants a chatterbox next to them on a flight!!