Dance That's a nice list. I think one of the key things that makes me happier than some other people is I know what I like. So - for example- I hate travelling, just don't like it, more of a homebody, so I limit how much I do in my job and try to take staycations as much as possible. Then I feel refreshed and really enjoy my home and friends around me instead of feeling stressed out trying to catch a plane and discover where to buy food at 10 o clock at night with the children howling.
I also try to ignore 'shoulds' of which there are a lot on MN. Apparently it's quite lazy to stay in your PJs all day and not go out on the weekend and do some improving exercise like bike-riding- great if you love that, but if you are tired out, then a nice nap might actually set you up better than riding around, unless that's what you all love to do. Knowing what you need, and what makes you happy/energized is definitely important- I have friends who seem always exhausted and ill because their schedule is just over-full but they seem to think there's something bad about admitting defeat and not having that extra dinner party/friends over on the weekend.
I think being true to yourself, and not having to pretend too much in your work or your relationships, makes you happier, being yourself is immensely freeing, even if the real you is slightly less dynamic and go-getting at times than you might like.
The final thing is luck though, I am lucky that although most of my family have MH problems, I don't and have never really had depression. I did once and it was just awful, so anyone with long-term depressive illnesses, even if they tackle them and get help and so on, that's going to be a harder life than if you are lucky enough not to have them.