You're totally right that everyone is different and there's no One True Solution here. Which, I guess, is kind of what I was trying to point out.
I think your 1 and 2 are excellent bits of advice, even if convincing yourself to maintain them in the long term can be tough.
We (tech people) live such sedentary lifestyles that I'd suggest just a direct command of 1. WORK OUT (at least 20minutes of raised heartbeat each day) and 2. EAT WELL (whole foods/balanced/non-processed diet)... Are you doing this now? Well, get off your lazy ASS and BIG BELLY and JUST DO IT! :)