What are some basic things I could do to reduce the start-up time? 

Is there anything in particular I should pay attention to, for that matter?

Note: Startup time can be mitigated by starting Emacs less often (once per session) and [opening files in a running instance](https://www.gnu.org/software/emacs/manual/html_node/emacs/Emacs-Server.html#Emacs-Server). This question is about minimizing the startup time, for the session start or any other time when starting Emacs is necessary.

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See also the [same question](https://stackoverflow.com/questions/778716/how-can-i-make-emacs-start-up-faster) answered on Stack Overflow, with question and answer scores over 50 and 30-some "favorite" bookmarks. Good answers here should go beyond what is available on Stack Overflow.