Have you tried your couch facing the tv, so it is more comfortable for viewing, but also to split the room as you are wanting. You could then place the green hutch on the opposite wall, so things are not lined up along the other wall with the window. Add lots of pillows on bench under window to make it more comfy and feel fuller. In regards to the back wall, you may want to look at photos on Houzz to get ideas that work for you. I think you basically need less of the smaller items (furniture and items on wall) to make that wall feel less cluttered and have a larger impact. Hope your room allows for this layout. Good luck.

Is the chest on the left wider than the one the TV is on? What's under the TV should be 25% wider than the set. I'd want to unify the bookcases and the TV better to make a focal point of them. Looks like you have plenty of books, so I would make the bookcases dedicated to books only. There is not enough room for decor items on the shelves, and all the little items you have stuck around the books are not large enough to be proper decor with the books. Can you get a third bookcase wide enough to remove a shelf and insert the TV? This would give you more space to arrange both books and decor, and would solve the current problem of a disjointed look with the three items. Another idea would be to wall mount the TV between the bookcases. If your sofa weren't so large I'd suggest floating it facing the TV to divide the room visually with a cabinet or sofa table behind it to be used as a serving table for the dining room too.

I echo with Maureen's suggestion, can you use the sectional as a divider by turning it towards the TV? The space seems pretty tight.

Do you suggest I buy a shorter and longer tv stand?

I suggest you need an additional bookcase which can be converted to hold TV too.

As suggested, Can you rotate the couch so it's back is turned to the dining table? I like Deco's idea to get a third bookcase in Which you could put the TV. If you can't find one that works, then get a console that is wider and joins up with the current book cases. Maybe a cheap one from Craig's List that you could paint white if you can't find one new that you like.

Do you have any lights near the couch? As a reader, I always want a lamp where I sit.

Could we see the other three views of the space, please?

I would put a very simple credenza like this between the bookcases. (This is 69$ from Wayfair.)

If you want it to look like the unit is all one piece, you could glue a piece of molding over where the pieces come together. You can use the piece the TV is on now under the window. All that baby stuff is so precious!! Makes me all teary eyed.

This is view from where the TV is

Lower the mirror, or maybe put it someplace else so people don't have to see themselves chewing. Remove the art from the end wall of the dining area. Lower the art to the left of the arched doorway to about an inch above the switchplate.

Definitely get a longer TV stand.

What's behind the sofa?

Assuming you are working with a budget, I think the easiest thing to do is lose the bookcases and move the TV onto the blue console directly across from the sofa. The bookcases might go in a bedroom but don't belong in this room and they seem to be the main thing that is bringing the room down. That one large wall at the end is your only hope for a focal point for the room. Get a large credenza and top it with beautiful artwork, lamplight, and an accessory or two. Take the family pictures down from the wall and put them on a table somewhere. I would also lower the mirror over the dining table and get a better arrangement for the dining table, so that it reflects in the mirror. I think it would also look nice to hang roman shades over the windows (on the outside of the frame) to give some interest to the windows without taking room space. I would hang the shades a little above the windows to give them the illusion of being a little taller. For inspiration for the focal wall, check here: http://www.houzz.com/projects/1295077/art-original-abstract-paintings A few suggestions:

Behind the sofa is a "window" opening to the kitchen

If there is a window to the kitchen there, then I think we need some rearranging. Showing us a photo of that wall would help.

Do I put pictures behind the green buffet?

Didn't see any specific colors in your room so I am just throwing this out as an example. I pulled some blue things that you can intersperse in the bookcases to tie things together. Do you need all the books? I would clean out about 1/2 of them. Then some pillows for your sectional. You could add others that you like to them. These things are all from Etsy.

Can you sketch out the room (showing windows, doors) and give dimensions?

Maybe sit the tv on the turquoise chest and pull the sectional and rug forward three or four feet. That you allow folks access to that past thru.

What is that cupboard in the corner of the dining room that is white and blue/green? can you put the green buffet there? Can you put some of the dining chairs away and make the table smaller?

If it were my room, I would move those bookcases out. They are functional but not all that nice looking. Maybe put into a kid's room for books and toys.

Then I would put the turquoise chest under the tv and swing the sectional to face it. Maybe wallpaper behind the tv. For now, I would take all the decor down from the walls.

Maybe a gallery wall where the mirror is in the dining room.

A chandelier over the table will give the mirror something to reflect. I'd look for something linear since the table is so long.

With the kitchen pass thru and the left facing chaise, it might make more sense to put the couch on the other wall and put the green chest under the pass thru, perhaps with chairs on one or both sides. Then the chaise will form a divider between living and dining.

Or, could the tv go into that back corner, angled a little? Then put the chaise along the window wall. In front of the window some, so there is room for drapes to stack.

This photo shows the tv in a back corner (they aren't really pretty, afterall). And for colors: run with the teal/turquoise/white/gray.

Think about wallpapering that dining room wall with a paper to bring more teal into the room.

The Achilles Heel is really the sectional. Is the sectional one piece, or can you make two pieces out of it - it would help with arranging your room.

Drapes will help to bring the room together also. These would blend with the walls and go with the wallpaper above.

The sectional is one piece.

Perhaps sharing a few of ours designs will help inspire you.

I will redo the focal wall with a longer TV stand that connects to the bookshelves but for now does the couch and green buffet replacement make for sense now?

I think the question is, does it work for you? Also, if you can swing more of a built in look with the bookcases, that would be great. In the picture below, your TV would go in the middle.

I think a TV stand that spans the space between the bookcases will bring that wall together. Removing the photos from that wall has totally calmed the room. You could stand to edit the shelves a bit so you have more open space, add curtains, and probably a piece of art over the sofa between the windows.

Add a couple of green sofa pillows to echo the green chest.

Would the blue or green chest fit next to the sectional? Ex.

Looking so much better!

Editing the shelves as suggested next. Take the things off the top of the two bookcases. Pull the sectional forward three or four inches so you can hang drapes.

Let's find a new spot for the mirror hanging next to the pass thru. It is too high there and too large.

I actually like full bookshelves, but put more of the heavy books on the lowest shelf. And turn some on to their sides. Add a small object on top of some.