I was recently reading the Skeptics.SE FAQ, and one of the top lines of their faq is:
New users (even users familiar with the StackExchange format) should read our introduction to the site before posting
The link listed goes to a very newbie-friendly meta post which explains what SE is, how it differs from online forums, and the sort of quality expected from both questions and answers.
I loved this, and would love to see something similar implemented in all SE sites. I made a similar proposal over at The Workplace a few weeks back, but see some other SE sites that could probably use something like this as well.
I think new users are much more likely to read a page specifically designed to introduce them to the site than they would be to read the entirety of the faq. The FAQ is quite long, and contains a lot of things that are not relevant to new users right away.
A separate page or meta post designed specifically for new users could teach them how SE is different from other forums/Q&A sites, how to ask good questions, and anything specific to the SE site that users should know before posting, all without cluttering the FAQ further.
In addition, it can help alleviate the perceived hostility that is sometimes mistaken by users who don't fully understand a SE site yet, and get negative feedback from other users.
So my proposal is to create a generic, friendly, welcome-new-user page or meta post that can be edited by individual SE communities, and that teaches new users whatever they should know before posting, such as
What SE is and how it differs from online forums
That SE sites are focused on a specific topic only, and provide a link to the faq section on what is on-topic
That we have a specific definition of what makes a Good Question, and a short example with a link to a longer article on what is a Good Question for SE
Anything specific to that specific SE site, which may or may not include
How to ask good subjective questions (only for subjective sites)
That answers should be backed up with references/personal experiences, and should not just be "me-too" answers that repeat other ones (possibly only for sites where the topic is one that all users feel they have some knowledge of, like The Workplace)
Where/What the Meta site is (only for non-meta sites)
What downvotes votes mean (only on sites where down votes are very common, such as MSO)
Anything else you think a user should know before posting
and to add a line to the very top of the faq that says something like
New User? Click here and read our site introduction before posting
This will provide a more welcoming page for users new to SE, and I think new users will be much more likely to read a welcome-new-user page than the faq, so it will help reduce the number of truly terrible questions that get asked (sadly, nothing I can think of will eliminate those entirely).