Google Blogoscope’s article on Creating a Good Blog Archive is a collection of 20 tips for bloggers that are seriously worth considering. They include clean and streamline CSS and designs, skipping clever post titles for informative ones, explaining more than necessary to help people understand, separating content from layout in your design, and streamlining your blog so it will move easily from one blogging tool or website to another, if necessary.
On the web, there’s no easier way to provide context for those who need it than using links – because it’s unobtrusive for those who don’t need this context (they may simply not click on it and ignore the link). That’s why it’s good style to always link to relevant previous posts if it’s an ongoing discussion (e.g. when you write “as mentioned yesterday” or “last month’s contest”). This way, visitors can read your archived posts months or years later and still know what was going on.