Trying to find balance between people for whom online activity is second nature and those who only dabble is difficult. Here are just a few basic rules that I see violated a lot - both for the techies in talking to the non-techies and the non-techies in how to behave in an online world:

1. Follow directions and look around - "Intuitive" is such a silly term because intuition is so different for each person. Feel free to actually read directions (if given) and explore (Google can be your friend) both for the content your looking for and help on how-to's. Following directions also means putting appropriate things in appropriate places. I have received e-mails where the content (or at least important information) is in the SUBJECT line, not the body. The SUBJECT line is for the SUBJECT. The body or message area is for the actual content and many people (or at least me...) don't read subjects every time, leaving them scratching their head trying to figure out what you're talking about.
2. Give directions - For those who are used to staring at their computer more than human faces, remember that many others don't understand computers the way that you do. Offer as many directions as you can (in non-tech language). Feel free to link to them or point people to them so they don't clutter up your content too much, but remember that the people you're directing are there because they don't know what you're talking about.
3. Explain yourself - This goes for both sides. Techies can see #2, but it also applies to not saying things like "Click on the URL." Many will say, "What's a URL?" Keep your language non-techy for the most part. Remember the audience! Non-techies, this means that techies can't help you unless you full explain the problem (even if it's not in techy language). Saying "it doesn't work" elicits a "what do you mean?" response.
4. Balance the info - Don't dupliate something that's already been given (for example, the date need not go in the subject or body of an e-mail because it's automatically a separate line), but don't leave out helpful instructions just because it's obvious to you.