It's hard to know without seeing the rest of the room, I think.

I see nothing mid century about your room so far. I would de-clutter first then design around storage required.

You need to prioritize what the room is going to be used for. Your stating its for work, sewing, bedroom, and library. Mid century modern? Very hard to do in a multi functioning room. Good luck!

Agreed, mid century is a fairly bare bones look, and you have a multi-purpose room. Where are the windows situated? That's where I would want to place whatever you spend the most time on, presumably your office desk.

Love MCM!! Low Danish sofa with orange chenille cover. Accent pillows (24" - large) in teal and a teal/Orange print, with button backs. Use heavy, loose-weave material if you can find it (I made some that I love).
Simple teak table, wishbone chairs. Your desk chair looks fine.
Use a modern, patterned area rug, and paint the walls some other color; this is too yellow, at least in the photo.
Desk in the corner may be ok; can't see it too well..
Use simple large prints on the walls, perhaps framed Marimekko swatches.
Teak bookshelf unit.

Maybe you need a full height storage unit on the wall behind your desk. Then, you can have some fun selecting furniture!

Thanks for all of your suggestions, I am making real progress and will post pic soon.

Okay gang here is what I have done so far. Remember I am a teacher working full time so I am on a budget. I think I am going to put a large b&w photo on the wall. this is just a baby step, I also found some cool orange fabric in my fabric stash so I am making curtains..... I also love working in wood and I am going to make a room divider

Lovely- keep the pictures coming!

There is more, I found an old desk chair, I have a sweet McCoy pottery collection, lots of yellow pieces, and some science stuff

Are the squares decals?

No I measured them out with painters tape on my quilting mat and then placed it on the wall