wordpress: managing settings
Size of the Post Box: How many rows of text should appear in the Post writing box by default? You'll want to change this if you use a very small or very large screen. However, note that in most modern browsers, you can change the size of the post writing box by dragging its lower right corner:
You can also use the Fullscreen button on the toolbar (circled, above) to use your full screen width for editing.
Default Post Category: If you forget to put a post in a category, it still needs to show up in some category. By default, this is "Uncategorized," but you can change the name of that category from the Posts | Categories manager.
Default Post Format: This should be "Post" for almost all sites.
Post by Email: Lets you create posts by sending to a special email address, which you'll need to set up on your server. The usefulness of this feature is debatable. When would you have access to email but not to the web? And if you have access to the web, why wouldn't you just post through the Dashboard? If you want to use it, full instructions are present in this section of the settings.
Remote Publishing: If you find the WordPress Dashboard lacking, you might prefer to use desktop software to publish to your WordPress site. In the past, tools as Ecto and MarsEdit were very popular. But as the Dashboard has evolved over time and gotten better and better, their usage has waned. If you do choose to use one, enable the protocol specified in the settings here, then configure your desktop publishing tool to match.
Mars Edit is an example of 3rd-party software that can be used for posting to a WordPress site without using the Dashboard.
Update Services: You can configure WordPress to "ping" an external service whenever you create a new post. Most such services are blog directories. You could potentially benefit from some increased traffic by listed in these directories, though these sites are not nearly as well visited as they once were.