Experienced Emacs users are fanatical about efficiency. In fact, they will often end up wasting a lot of time searching for ways to be more efficient! While I don't want that to happen to you, there are some easy things you can do to become a better Emacs user. Sometimes experienced users make novices feel silly for not knowing all these tricks--for some reason, people become religious about using Emacs ``correctly''. I'd condemn that sort of elitism more if I weren't about to be guilty of it myself. Here we go:
When you're moving around, use the fastest means available. You know that C-f is forward-char--can you guess that M-f is forward-word? C-b is backward-char. Guess what M-b does? That's not all, though: you can move forward a sentence at a time with M-e, as long as you write your sentences so that there are always two spaces following the final period (otherwise Emacs can't tell where one sentence ends and the next one begins). M-a is backward-sentence.
If you find yourself using repeated C-f's to get to the end of the line, be ashamed, and make sure that you use C-e instead, and C-a to go to the beginning of the line. If you use many C-n's to move down screenfuls of text, be very ashamed, and use C-v forever after. If you are using repeated C-p's to move up screenfuls, be embarrassed to show your face, and use M-v instead.
If you are nearing the end of a line and you realize that there's a mispelling or a word left out somewhere earlier in the line, don't use or to get back to that spot. That would require retyping whole portions of perfectly good text. Instead, use combinations of M-b, C-b, and C-f to move to the precise location of the error, fix it, and then use C-e to move to the end of the line again.
When you have to type in a filename, don't ever type in the whole name. Just type in enough of it to identify it uniquely, and let Emacs's completion finish the job by hitting or . Why waste keystrokes when you can waste CPU cycles instead?
If you are typing some kind of plain text, and somehow your auto-filling (or auto-wrapping) has gotten screwed up, use M-q, which is fill-paragraph in common text modes. This will ``adjust'' the paragraph you're in as if it had been wrapped line by line, but without your having to go mess around with it by hand. M-q will work from inside the paragraph, or from its very beginning or end.
Sometimes it's helpful to use C-x u, (undo), which will try to ``undo'' the last change(s) you made. Emacs will guess at how much to undo; usually it guesses very intelligently. Calling it repeatedly will undo more and more, until Emacs can no longer remember what changes were made.