I've often had half-finished LW post ideas and crossed them off for a number of reasons, mostly they were too rough or undeveloped and I didn't feel expert enough. Other people might worry their post would be judged harshly, or feel overwhelmed, or worried about topicality, or they just want some community input before adding it.
So: this is a special sort of open thread. Please post your unfinished ideas and sketches for LW posts here as comments, if you would like constructive critique, assistance and checking from people with more expertise, etc. Just pile them in without worrying too much. Ideas can be as short as a single sentence or as long as a finished post. Both subject and presentation are on topic in replies. Bad ideas should be mined for whatever good can be found in them. Good ideas should be poked with challenges to make them stronger. No being nasty!
I agree. LW doesn't have many posts about maintaining and improving the brain.
I would also add aerobic exercise to your list, and possibly drugs. For example, caffeine or modafinil can help improve concentration and motivation. Unfortunately they're habit-forming and have various health effects, so it's not a simple decision.
I've only had modafinil once (but it was amazing in the concentration-boosting department), but I have a lot of experience with caffeine, and the effects are primarily mood-affecting, for me. Large amounts of caffeine destroy concentration, offsetting any improvements, and, like other drugs, the effect grows weaker the longer you take it. On the plus side, caffeine is only weakly addicting, so you can just stop every now and then to reset things, which I do every few months.