My personal favorite time-saving measure is building 3D models of recurring backgrounds, and using those as reference to draw all my backgrounds from. That way I don't have to sit and math out the perspective of a scene, I can just rotate my 3D model to the right camera angle, take a screenshot, and bring it into my drawing program and trace over it.
3D Model
I build my models in TinkerCAD, which is aimed primarily at children, so it's super easy to use and has a lot of really easy tutorials to walk you through navigating your workspace and creating complex shapes.
Import to Drawing Program
Then, using my thumbnails or pencils as a reference, I rotate and zoom the camera in TinkerCAD to the right position, take a screenshot, and import that into my drawing file. It can take a couple tries to get the angle right sometimes, but I almost always get it right on the first or second attempt.
Trace Over It
Lately I've been using Clip Studio for my backgrounds because I can turn on the perspective rulers, snap my vanishing points to the lines already established in my 3D model, and draw without having to worry about my lines not being in perspective. Serious time saver right there! Then just hide the perspective ruler layer to draw things that don't go to my vanishing points, and it's great.
Done!
Bring it back into Photoshop to draw my characters and finish up the coloring and word balloons and whatnot.
This whole process isn't really necessary for a short scene in one location that will never been seen again, but for a long scene in one place, or a location that the characters keep going back and revisiting, it saves me a ton of time. And I don't build my 3D models very complex, I add most of the detail as I'm inking it in Clip or Photoshop. For example, this scene in a different comic I did...
I did all of my backgrounds from this 3D model I built of a froyo shop...
The model itself is not very detailed at all, but it helped me establish some complicated perspective tricks, especially along the curved wall, and helped me keep everything to scale.