Various methods I guess, here’s a simplified version of what I do.
I wrap the content call in the template with a div like this...
<div id="page_content">
[*#content*]
</div><!-- close page_content-->
Then use <h1>’s <h3>’s and <p>’s and the likes in the actual content
<h1>heading</h1>
<p>rambling textual stuff</p>
Then in the css I use...
div#page_content h1{
font-size: 2em;
}
div#page_content p{
color: red;
}
etc...
I think that’s a fairly accessible and search engine friendly way of going about it.