You did not say the measurements of the room. I really like the tiered shelving unit in the corner. I would attach some kind of system to hold your rulers, etc. to the sides, maybe just the length to the second shelf. Maybe put a board 1/2" or 3/4" thick across the top, attaching a pegboard piece or a piece of Plexiglas to both sides. Bring that down only to the second shelf but that will give you room for the pegs. Then you could hang all your rulers on it.
I would buy the plastic Darice Stackable Organizers which measure 14" x 14" x 3-1/4" high, and stack them with projects in on the other shelves. Measure the shelves before you buy so they fit right. I got mine at AC Moore and I love them. If you are working on a quilt, all the 12-1/2" x 12-1/2" blocks fit into it nicely. I just got them for 2/$10. I do not buy the ones for paper crafting by another company because they run about $16-19 a piece. They go on sale at least once a month.
From experience in working in offices, I never put my back to a door. So I would place your sewing desk towards the middle of the room with your back at the wall, or maybe put the bookcase behind you. That way you can reach things on it but it is not taking up other wall space. I would try to keep all the furniture the same color because the more unity in the room the better.
Try to keep the fabric on shelves in the closet to keep them clean and away from the light for fading. I ruler fold mine and stack per groups, i.e. greens, white, small prints, large prints, etc. If you have room, buy a few plastic drawer units with rollers on the bottom and place them at the bottom of the closet. I got mine at garage sales for $3 a piece. Use them for whatever, but I use them for fat quarters and scraps. That way you can roll them out if working on something special, or even take the drawer out.
I would get about 2 bookcases and use them for whatever you need, maybe your quilt books.
I notice you have a table in there, I would back that up to the other side of your sewing machine table. You could use it for cutting as well as sewing on a large quilt. If you can find another chest, I would make an ironing board for the top. Get a board the size of the top, cover it in several layers of flannel or use an old flannel sheet, and then a cotton top. Staple it down and then place it on the top of the chest. Storage in the chest.
I would try to get task lighting for the room, or switch the ceiling light out for a long tube light. I hate overhead lights because I get headaches from them but they get you into the room.
I have studied a lot of what I want because we will be putting our house up for sale and I know what sewing room I want in the new place. My sewing room right now is about 10' x 8' but I have all white furniture and shelving with an "L" shaped sewing surface. I bought the white photo boxes at Michaels, or AC Moores and I use them for zippers, etc. and put the name in the little slot. It really looks nice. I have collected the wicker picnic baskets over the years and have projects in them on top of my bookcases. My next room better be a big one, just for me, or else my name does not go on the dotted line. haha Hope this gives you some ideas.