I recently came across this question from 2010, which basically asks, "How do I get better at coming up with proofs?" This is an interesting and valuable question, but there's never going to be a final answer; there's always something more to add. Is it considered acceptable to add my own two cents to such a question?
There are several related questions on the meta about resurrecting old questions (see e.g. here and here), but as far as I can tell, these all pertain to specific questions with an objectively correct answer. By contrast, in this case there are many good answers that each address some facet of the broad question being asked (for example, one person discusses how to practice, another gives some specific techniques, another recommends a particular book).
To put this another way, if this question were asked for the first time today, I would want to add my answer to the existing ones. Should the fact that the question is several years old change that?