I have not told you everything there is to know about Emacs. In fact, I don't think I have even told you 1% of what there is to know about Emacs. While you know enough to get by, there are still lots of time-saving tricks and conveniences that you ought to find out about. The best way to do this is to wait until you find yourself needing something, and then look for a function that does it.
The importance of being comfortable with Emacs's online help facilities cannot be emphasized enough. For example, suppose you want to be able to insert the contents of some file into a buffer that is already working on a different file, so that the buffer contains both of them. Well, if you were to guess that there is a command called insert-file, you'd be right. To check your educated guess, type C-h f. At the prompt in the minibuffer, enter the name of a function that you want help on. Since you know that there is completion on function names, and you can guess that the command you are looking for begins with ``insert'', you type insert and hit . This shows you all the function names that begin with ``insert'', and ``insert-file'' is one of them.
So you complete the function name and read about how it works, and then use M-x insert-file. If you're wondering whether it's also bound to a key, you type C-h w insert-file , and find out. The more you know about Emacs's help facilities, the more easily you can ask Emacs questions about itself. The ability to do so, combined with a spirit of exploration and a willingness to learn new ways of doing things, can end up saving you a lot of keystrokes.
To order a copy of the Emacs user's manual and/or the Emacs Lisp Programming manual, write to:
Free Software Foundation
675 Mass Ave
Cambridge, MA 02139
Both of these manuals are distributed electronically with Emacs, in a form readable by using the Info documentation reader ( C-h i), but you may find it easier to deal with treeware than with the online versions. Also, their prices are quite reasonable, and the money goes to a good cause -- quality free software! At some point, you should type C-h C-c to read the copyright conditions for Emacs. It's more interesting than you might think, and will help clarify the concept of free software. If you think the term ``free software'' just means that the program doesn't cost anything, please do read that copyright as soon as you have time!