As far as the use of Quills is concerned, I think I could have been accepted as a Hogwarts student. … Back in my childhood or teens (long before Harry Potter first popped up in J.K. Rowling’s mind), I used to practice writing with quills made out of crow-feathers. (Just for fun. I’m not quite so old that I did not have access to pens and pencils.)
In The Order of the Phoenix there is a nasty Quill in use which does not need dipping in ink because it uses your own blood instead. Harry is forced by Professor Umbridge to use it to write the text “I must not tell lies” and the words appear on his hand instead of on the paper.
Another famous quill from the Harry Potter books and films is the Quick Quotes Quill used by reporter Rita Skeeter in The Goblet of Fire. This is a magical quill that automatically twists whatever you say into sensational newspaper stuff. I’m not so sure those aren’t secretly used by Muggle reporters as well!