I work for an international charity and do lots of miles, always on the cheapest ticket. Never had an upgrade and never collected enough miles with any particular airline to get any favours from them. So, cattle class it is - moo!
For daytime flights I always take some work to do and a couple of good novels (I borrow them from the local library). Then I settle down to read the novels, feeling very virtuous that I have some work in my bag and that I could get down to doing some if I wanted to - I never seem to want to.
On night flights, I don't eat the meal they serve immediately on take off - it always keeps me awake.
On all flights, I take off my shoes (don't have any clever socks - but I should get some), take any glasses of soft drinks that are offered to me whether I feel thirsty or not, always have water alongside any booze with the meal and I get up and walk around every hour or so.
I always get aisle seats whenever possible. It's a personal thing, but I prefer being disturbed by others when they go to the lav, than to ask others to move when I go. As I get older, loo trips seem to be getting shorter, but more frequent!
I really haven't noticed much difference in the quality of service between different airlines. You have good flights and bad flights on all of them. What does make a difference is how friendly the cabin crew are. But, bear in mind that while the pax are all trying to sleep, the crew are working a long shift. I reckon that the crew will always find it easier to be nice to me, if I'm friendly and helpful to them. So, I try to greet the crew with a smile and a friendly hello (in their own language if I can manage it) and I watch the safety briefing. Don't know if it helps, but it doesn't take much of my time.