Location, location, location

I don't think the Dock works particularly well at the bottom of the screen. Apple places it there because it makes the screen look balanced. But I want my document windows to be as tall as possible, and the Dock gets in the way.

Instead, I pin the Dock to the upper right corner using TinkerTool. This has two benefits: First, the right edge of the screen is typically unused (especially if you don't put your drive icons on the desktop), and thus is available space. Second, the Dock icons themselves move far less, thus making it easier to click frequently-used items quickly.

Every icon in is place, and a place for every icon

The Mac OS X Dock can be a wonderful organizational tool if you don't overload it. Populating it with tons of application aliases, and using it as a general app launcher doesn't work well. Use LaunchBar for that.

I use the Dock for application switching, not for application launching, so that there is no visual confusion about which icons represent running apps, and which are mere aliases.

Who needs the old Apple menu?

One of the nicer things about the Dock is that any folder dropped onto it immediately generates a hierarchical menu structure, as we had in the old Mac OS 9 Apple Menu. For people making the transition from Windows to Macintosh, this can function as a nice replacement for the Start menu.

The Dock is also a good place to put collections of documents that don't change, for example, folders of boilerplate documents, or in this case, an array of network aliases (in the illustration below, these are Fetch FTP bookmarks).