Although this achievement seems somewhat daunting at first glance, it's really not that difficult. If you've already been hunting Pagies and other collectibles in each Grand Tome, chances are you're already close to hitting each world's 200 Quills. By the time I got to the final Pagie in each Tome, I already had about 190 Quills per Grand Tome.
While I'm not going to plot out all 1010 Quill locations on a map, here are some tips for hunting and some locations of hard to find Quills that had me running in circles.
Tips and Tricks
The biggest tip I can give you is to look everywhere. If you can see a location and can go there, chance are there are some hidden Quills in that location. Some Quills are obviously much more well hidden than others so don't hesitate to search every nook and cranny you can find.
Once you get down to 10 Quills remaining, you are able to make use of Vendi's Hunter Tonic. This Tonic will notify you when a rare collectible is nearby via a noise in the game or a controller vibration. Don't expect to use this for all 200 Quills in a Tome though. The Tonic only tracks "rare" collectibles, which means there must be 10 or less of them remaining.
-There are a few Quills hanging out on top of the rock you walk under immediately exiting the area. Fly up or traverse the rocks on the edge of the map to reach them.
-After you defeat Rampo and claim his Pagie, make sure to hop behind him to add a few more Quills to your collection.
-After talking to Shovel Knight for the first time, head to the back of the temple, with your back facing SK's location. If you jump off the ledge and begin gliding, there is a single Quill on a small, grassy ledge below the temple.
(Not many difficult locations in this area, I was only missing 3 once I collected a majority of the Pagies)
-In the lake in the center of the map, there are quite a few Quills hanging out under the surface of the lake. Dive down or use the underwater breathing ability (if unlocked) to snatch these up.
-In the area with a Time Trial, accessible by rolling across a ramp and going through a pipe, there are a few Quills on the track that you may have missed the first time around. These are all easily visible by traversing around the track.
-On the platforming sections with moving logs, there are a few Quills off to the sides that are easily missed if you don't check your surroundings before crossing the river.
-Along the ledges of the House of Cards there are a few Quills that can be missed if you don't fly around this area much.
-Inside the large central fountain, there are a few Quills along with a couple Casino Tokens.
-Near Vendi's location under the golf course, there are a few Quills along the wall that easily blend into the environment.
-Around the backside of the starting island, there is a destructible meteor hiding a few Quills under it. Destroy the meteor with Grenades or the pirate ship cannon to claim them.
-In the area with a couple outhouses, each of the blue outhouses can be hit to open up and reveal a single Quill inside.