Some years ago I had a living room that was 11 feet wide and 25 feet long. There was a separate dining room (forming an L with the living room), but no family room, so I had to include TV watching in it. I treated it effectively as two rooms, almost as three. I put a sofa against the longest wall, centered relative to the opposite wall, which was shorter because of the dining-room L and because of the door to the entrance hall, and placed two upholstered chairs next to it at right angles, forming a U. Since there was no fireplace or any other obvious focal point, I placed a long, low bookcase opposite the sofa, with a large painting above it and straight chairs at either end. I put the TV at the end of the room, with the furniture for watching TV turned away from the sofa group. There was also a separate seating area at the entrance-hall end, consisting of two chairs and a small table. This small seating area was not especially functional, but necessary because of the traffic flow.

It’s a long hall and I would attempt to pull it all together vs just adding something in one spot. By front door you could add a mirror, then use a runner where hall straightens out and a console, art and lamp on wall #1. It will have a nice flow and be welcoming.

I can't speak regarding exact sizes or dimensions...the size of things you should or should not get but.... I can give some thoughts on overall layout and placement of furniture. First, I'm assuming from the photo that the kitchen is attached to living area? I seem to see kitchen sink in foreground of photo? Either way, for a long narrow room and where you want a couch/seating, I personally think it's important to try and 'soften' the room...because it's long and narrow, whatever you put in the room could add to that boxy or straight/hard feeling. When I say 'soften' I mean... I like furniture at slight angles...or not perfectly straight. I never press a couch directly against the wall. It feels stiff and feels like lack of air flow ('chi'). I would pull couch at least 2" from wall. Also, instead of one long (stiff/straight-looking) couch, how about a loveseat, and then 1-2 chairs on either side of the loveseat or couch, turned at a slight inward angle ...so the loveseat and the two chairs almost create a very soft C-shape? I'm also a fan of round side tables vs square ones, again, to help 'soften' hard lines. Put a round side table between the loveseat and one of the side chairs. Another option is to add a pedestal light with a globe lampshade, at either end of the couch. A tree plant in one of the corners of the living area (say one of the corners by the entry door) creates a focal point, adds 'life' to the room and vertical interest.

THere are decorative magnetic grille covers that you can order to size. Or you could put a decorative wall grille like this one with hooks to distract attention.