I am making documentation for my client, with sections such as "How to add contents with inline images and videos", "How to create pages" etc. Is there existing reusable and easily understandable screen-shot documentation? If not, what are the key components of documentation for a Drupal site? What are common end-user stumbling blocks in Drupal-based sites and how can I best educate my client in basic Drupal concepts relevant to them?
Not being pessimistic :) but I have never seen good re-usable documentation for end users. IMHO it can't be done because Drupal is just too flexible. For instance, there many ways to add images to content (filefield, media, wysiwyg, imce), just like there are many ways to add content to the front page (promote to front page, nodequeue, views, panels). End user documentation is always dependent of how the developer built it.
When I train our clients how to use their new Drupal site, I take a two-step approach.
First, I quickly get them up to speed with some basic concepts, like:
Second, I show them how to do things on their own site, focusing on their daily routine and how their new site will make that easier. Usually I train end users in real life. If that's not an option, screenrecordings (video) with spoken explanation tend to work better than screenshots with written explanation.
Hope that helps.
I typically will use ScreenSteps or Clarify App from Blue Mango Learning to do just that, preparing each lesson with the "How to.." or "How do I..." approach then organize them into chapters, and exporting the manual into a html and upload to the server.
Clarify App for example, allows you to quickly do up a guide, upload it into clarify-it.com and get a short link for sharing. Pretty useful for quick / ad-hoc questions.