Many sites don't really require instructions. But as companies move more of their business out to the Web, we often expect the customer to do more "self-servicing".
We now require that well-designed site must be self-aware and self-evident. Such guidance can be provided through good visual design, well-written intros, context-sensitive popups and engaging, appropriate mini-presentations.
Frequently Asked Questions show that you understand the situation. "I anticipate your question. Here's the answer."
Quick, easy answers
The ideal content of an FAQ section is a list of the problems that users most frequently face - in other words, they are usability issues that haven't yet been addressed yet in the design. FAQ's as Problems
New visitors to a site often go to the FAQ's section as a shortcut introduction. Including FAQ's prominently as a regular part of site design can be helpful.
In addition to a dedicated index page of FAQ's as a menubar link on the site, a context-appropriate FAQ link should appear on any page where it's relevant. It opens the FAQ popup window and links directly to the appropriate answer anchor.
I like to present the FAQ answers in a separate window popup, so that you can invoke this valuable page of help information from anywhere on the site and still not lose your context.
If you find you've got a bunch of FAQ's focusing on a particular topic, then you may want to create a mini-presentation video Tutorial.