Wow! I'm loving this!
I agree with lots of the answers... eg movement (I dance every day, even if just around the kitchen), maintaining a healthy weight, good posture, general grooming/skincare routine, weight training (I love kettlebells), having your style and colours done, and orgasms 
The areas I'm feeling I could up my game are:
Brows - I've always had naturally strong, dark brows but have had permanent make-up in the past to fill them in which has long since faded. Have been wondering whether to try threading (I've always just plucked) and maybe microblading.
Lashes - my lashes are fairly good (and I find the super cheap Essence Falsh Lash mascara from Wilko is amazing) but I've been pondering trying extensions for more length/wow. I wasn't that impressed the one time I tried them years ago tho - they looked long but not thick enough for my liking. And iirc it was a faff with washing my face. Have they changed or do they vary?
Teeth - I had them whitened years ago and it made a positive difference but I found it made them unbearably sensitive for a while. Have techniques changed? What kind of whitening would you recommend? Also intrigued by Invisalign!
Some other things I already do that I think make a difference:
OCM
Oil as moisturiser (and Vaseline over that)
Contrary to others who said 'good bra', I've got rid of mine and now almost go braless or wear bralettes... ooooh the comfort! I'm a 32E (yes properly measured and all!) so not small. I feel like my boobs have got perkier since doing so but it could be my imagination just because I feel so much more warmly towards that whole area of my body!
Eating fresh herbs with almost every meal (they're packed full of nutritious magic!)
Hot/cold exposure, eg cold showers and hot saunas. I don't do this to Wim Hof level, just try to have a brief cold spell in the shower daily after my warm one and a weekly sauna.