There are even cheap courses on Udemy that you can follow. One of the things that helped me was the sensory exercises like doing your whole morning bathroom routine in the dark. Basically what happens is it helps you rewire your brain when doing certain activities in a way that you are not used to and now parts of the brain that are underutilized become active.
Other things that have helped is doing math and sudoku puzzles. Video Games definitely help with hand eye coordination, quick thinking. Also apps like lumosity on a daily basis.
As far as skills go, practice, practice, practice, your skills will always get better. Look up the 10,000 hour rule by Malcolm Gladwell.
I also find that trying as hard as you can at something you find interesting in a new domain can be good for this. You hone your learning skills but I also find that other domains usually have general tricks and principals worked out that can be cross applied to other domains that haven't figured them out just yet.
- https://en.wikipedia.org/wiki/N-back
- meditation/mindfulness:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4403871/
Taking DHA/EPA and proteins as well as zinc might help too. There are studies conducted on this.
Also, from my personal experience: water fasting for >= 5 days (not only do you get autophagy and ketosis, you get a clearer mind too). If you are interested in this fasting thing, then I suggest consulting Valter Longo and his findings.
For short-term tactical needs I seem to learn better through video.
Also learning to manage stress should be a bonus.
They are what they are. I don't take drugs/supplements for it. I don't even get as much exercise or eat as wll as I should.
I haven't needed to work for the last 20 years. But I'm always learning new things (hard things, that I'm not good at), starting businesses, mentoring people, doing physical activity that just plain hurts because I've got arthritis, taking care of handicapped kids... pushing myself both cognitively and physically every goddamn day. If there's ever a reason to go upstairs, I run up there. I don't put it off. I do all the housework even though I don't like it.
I might drop dead of a heart attack tomorrow. But studies show that people who just keep grinding and moving forward tend to live longer and lead happier lives. I bet a lot of those studies are poorly designed bullshit. But to me they also comport with common sense.