Here is a short tip for beginners.
Use M-<DEL>
to delete (“kill” in Emacs terminology) back to the start of a word, and M-d
to delete up to the end of a word.
Use C-x DEL
to delete back to the beginning of a sentence, and M-k
to delete forward to the end of a sentence (we already covered moving by sentences and how Emacs defines a sentence).
Finally, refer to this post about deleting a whole line.
Note that all of these commands put the text in your clipboard so you can paste it elsewhere.