Being fallible (not being the pope) I learned some things from my Drupal installation. Dries asked me to keep a list of things, and this is a record of what I still remember.

Beware though that this list is focused on using Drupal for a personal blog.

You do not need the Blog module !
If you just want a personal blog, you really don't. I consider this vital advise, especially because not using Blog seems counter-intuitive and because it is described as:

Blog: Enables keeping easily and regularly updated user web pages or blogs.