I think I already do most of the things you "should"
I eat well, am "normal" weight, exercise 4 times a week, get 7-8 hours sleep a night and have no health problems, but ATM (and most evenings) I'm shattered. I often wonder how people who aren't so fortunate even make it through a day.
I've had a busy and quite stressful week at work and was very tired last night. When DC were in bed though, DH and I had a nice dinner (in our kitchen!) with a bottle of wine, so happily tipsy, but not hungover today and a fairly early night.
Today we got up at 8ish, had breakfast together and played a word game that DS1 had to do for homework. Then DS1 went out to play for a bit and DS2 and DH washed the car while I pottered at a bit of tiding. DS1 wanted to make lunch, so I helped him cook sausages with some salad bits and a steamed pud (his menu choice).
After lunch we played board games for a bit, then I watched some tennis. DS2 decided he was doing tea, so we made bagels (far too much faff for the results, but fun to do with DS) and after tea we all went for a short walk.
DC bathed and in bed after stories by 8pm.
So really, it's been a good day, but nothing very taxing. I shouldn't be this tired!