A quick way to build up your bookmarks bar is to drag and drop addresses from the location bar into folders on the bookmarks bar. This even works with Auto-tab folders, and folders of RSS Feeds.

This is a much quicker way to fill your bookmark folders than using the Bookmarks menu, and also has a few other useful features. For example you can drag a URL into an unused place in the tab bar, it will open it in a new tab. If you drag a URL onto an already open tab, it will load the page in that tab.

URLs can be dragged from your files, links in web pages and from the location bar at the top of every safari window.

If you want to file your bookmarks away somewhere that isn't in the bookmarks bar, a quick way to do it is to click the bookmarks icon at the far left of the bookmarks bar (or press Command-Option-B) while you are viewing the page you wish to save. Then, when the bookmarks page is open, the URL will stay in the location bar at the top. You are now able to drag and drop that into any folder you wish.