The problem with this list is it fails the “fluff test”. (My name for not-my-idea—sorry, I can’t locate the original source.) The “fluff test” is: a suggestion “do X” is useful only if the suggestion “don’t do X” is also plausible. Otherwise it is fluff.
So e.g. most political speech immediately fails the fluff test: “if you elect me I will focus on reducing crime” is fluff because “if you elect me I will focus on increasing crime” is not plausible oratory.
Apply the test to each item on this list and you will see that it’s all fluff.
I mentally added an epilogue to the post saying “of course, everything on this list is ‘obviously’ beneficial, so if you don’t do some of these things, trying to write a plausible explanation for why you don’t is a helpful exercise that may point in the direction of personal growth”, which made it more useful. Maybe the point of the post is that such an epilogue is implied, and ‘if I wasn’t such an idiot’ I would have realized that all along …
I personally don’t find anything on the list disagreeable (including the summarization and mentoring items).
Summarization is a pretty well established memory consolidation technique to improve long-term recall of information. The OP does not explicitly state this is the aim, but that was my assumption, and if so I think it is uncontroversial that that is beneficial.
Regarding the mentoring, the item on the list was “you would have a good mentor” (which I agree with) and then underneath is “One way to do this is to email people” (which I also agree with in the sense that emailing is clearly one way to do this—I do not necessarily feel this is a good way or the best way, but the OP does not say it is, just that it is “one way”).
I can see why you would disagree that you “should have a ‘good mentor’ by emailing people to request that they mentor me” (I also disagree that such an approach is close to optimal) but I do not think this is what the OP says.