If you can get away with it:
mount curtain rods to the ceiling around the perimeter and hide your clothes behind floor to ceiling drapes (clean white sailcloth or light weight canvass would be perfect. short of that, matching wood hangers, sweater boxes, and clear plastic containers should give a more organized and polished feel.

we lived in a similar situation in centreville... organization is key (boxes, etc.). uniform hangers also help a lot... as well as overall neatness (mentioned above by colleen)...

What will really help the appearance in this closet with out even starting on the dresser is to organize your clothing. my closet used to drive me insane until I organized. First organize by type of item, then by colour. With the color flowing properly it will be easier on the eyes!! Also, if you can handle it, I would paint the dresset white! and add some fun decals to it that maybe match whatever color of sweater boxes you end up with!

sweater boxes are not only esthetically appealing but they also stop your sweaters from becoming stretched or misshapen!! Hope it works out, whatever you choose!!

The best trick (as redneckmodern pointed out) is simply being organized. I recently cleared out and tidied up my closet as well, using a combination of boxes and open shelves. When choosing boxes, get a similar (or the same) color, and use it for storing items you don't always need. Use open shelving (you can get really inexpensive items at Target or Ikea) for organizing sweaters.

Also (again, like redneckmodern said!) getting the same hangars work. You seem to already be basically there. And finally, I really like to use the color method of organizing, similar to the controversial bookshelf organization. i just break it up into shirts, pants, and outerwear... and then break each section down by color. It adds a bit of cohesiveness, and also makes it a little easier when picking out clothes!

I would suggest installing simple floor to ceiling curtains in white or off white. Only a couple of holes in either the walls or in the ceiling, would be easy to patch when you move out. I cannot see the ceiling light fixture, but you could add a nice (& cheap) shade to soften the lighing, or ask the landlord if you can replace the fixture with a fixture with halogen spots to wash the walls with light. I did that with an old brass track light in my apartment kitchen. It was much better with 4 spot lights that that boring white glass globe that was there before. When I moved out, I didn't want it, so I just left it there for the next tenant. These ideas may make this space cozy, instead of making people feel uncomfortable walking thru your closet.

paint

wallpaper (or any patterned paper)

dump all non-wood hangers

bins/baskets

metal slide-on shelf dividers

I think I would try to make it not look like a closet and more a small hallway/room by getting some wardrobes with doors to hide your clothes. To keep it cheap and not too DIY, Ikea has a bunch to choose from as well as some clever shoe cabinets. Then put items in the top shelves in neat storage that also hides the contents (maybe fun colors?), and use an open shelf or a lower bureau so that it can fit into the corner. Decorate it like a room: a mirror somewhere, little pieces of art, a throw rug, and voila: closet, what closet?

http://www.ikea.com/us/en/catalog/categories/departments/bedroom/10449/
http://www.ikea.com/us/en/catalog/products/90111895

1) All matching hangers - get some more of the wood ones, get matching pants hangers and matching skirt hangers

2) Organize clothes by item (shirts, pants, skirts), then by color

3) Matching sweater boxes or baskets (I like the ones you have). Everything not on a hanger should be contained in some manner

4) Add color with the boxes, baskets. I don't think you have to paint the dresser as it blends with the rest of the white in the room.

5) If you can spare the storage, use the built-in shelves by the door to display items (e.g. apothecary type jars with soaps or other bath items), pretty folded towels, decorative things, etc.

6) This is going to sound really fussy, but even making sure your hangers are spaced fairly equally apart makes a closet look really organized.

I'd install a second level of rods for multiple hanging levels. Your clothes aren't quite stuffed in there, but if you notice fancy retail spaces they always have an inch or so at least between hangers which helps give it a neater feel and will make getting items in/out easier - so it will stay neat. So, a little more space would help it look tidier. You also don't seem to need as much shelf space, and the high shelving is never that functional.

After that, get more substantial hangers, hang your items grouped by length, and I think it'll look great.

Also, those shelves to the right are not being utilized. They are perfect for all the sweaters that are out of reach above which are collecting dust and falling down on you whenever you go for one. Put the boxes in those harder to reach places.

I lived in apt that had a wonderful and huge (floor to ceiling doors), very tidy lookoing ikea unit. It looked almost like built ins and hid everything.

Agree with above suggestions! Also, once you've organized clothes by type/color, seems you might have some space beneath shirts to place shoe racks or low shelves, keeping loose shoes tidy. I'd move the white boxes in the bookcase to your top shelf or on the dresser, and find some kind of simple box or basket - all the same - to place in, and fill, each nook in that unit. You'll get additional storage and it will give you a clean look. You've got great space to work with - good luck!

Take cues from your favorite clothing boutiques: Paint and/or wallpaper the walls, organize hanging clothing by type if not color (Skirts in one area, then blouses, dresses, coats...) and get rid of those nasty wire hangers! (But don't just throw them away - Bring them back to the dry-cleaners for recycling/reuse next time you take items for cleaning) and put the folded sweaters on the low shelves and the boxes in those shelves up on the overhead shelves.

Curtains.

I'm a huge fan of the Elfa system from the Container store. I use the system in various places around my house and have been very pleased - it helps organize and gives everything its own space. Plus, right now (through january I think) their everything related to Elfa is on sale for 30% off. Good time to buy!

i'd paint the back a light fun color (maybe a light blue or pink) that won't mess with the colors too much, make uniform hangers, and put your sweaters on those shelves, so the boxes go up top.

also, yes, certainly, organize. i have dresses and suits in one part of my closet (work/special occasion) and on the other side, pants, then skirts, then long sleeved shirts (color then white), short sleeved (color then white), no sleeved (color then white) and sweaters stacked on top.

As others have said, curtains are the way to go!

I once did this in a studio I used to live in on the super-cheap AND without making ANY holes. I purchased extra-long tension rods, used some clip-in curtain rings (Ikea) and re-purposed twin-sized flat sheets for panels.

Not only does this hide clutter, but it also helps to keep dust off your clothes.

As a side note, twin sheets are the best deal around to use as curtains!

I would definitely install nice & heavy floor to ceiling drapes that could easily be pulled back for you and pulled closed for guests. You should mount the rod from the ceiling and the drapes should be simple white with grommets.

I would still however, use the organizing tips listed above to better store everything behind the curtains. It will be nicer and more efficient for you and of course, your guests might peek behind to see what you are hiding.

I have the EXACT setup in my place. I have my clothes organized according to ROY G BIV and all my hangers are the same black plastic tubes Then I've divided by skirt, pants, etc. It helps a little. I am also on the room height curtains bandwagon. Hey, I might try it myself!

I would be tempted to hang ceiling mounted bamboo shades/blinds. You could leave it up until guests come over. I think curtains might be a bit of a pain for every day practicality. Let's face it, the easier it is to get ready for work in the morning the better. You will have maneuver around them and tie them to the side.

Even though you aren't suppose to paint you could and just paint it back white before you leave. I've done that. Endless your landlord likes to visit. Otherwise, You could get creative and take craft or scrapbook paper and adhere it to the wall. I believe there is special poster tape you can use a lot of college students use it dorm rooms.

Also you could hang some fabric with starch which can be removed easily before you leave...directions:
http://www.rentaldecorating.com/quick_fix_fabric_on_walls.htm

The two things that make me smile everytime I walk into my closet:

1) Matching hangars; and,
2) Bright pink walls.

Honestly, I would install medical curtain tracks and hang curtains:

http://www.cubiclecurtainfactory.com

No matter how tidy you make it, you're still going to be asking guests to walk through your closet. Granted, that might not matter to you or your guests, but it would bother the hell outta me! (Not to mention that my sister would walk away with half my wardrobe.)

Lots of luck!

Eveyone had great ideas -- I agree with ExpatDecorator that it would probably be worth painting one wall if you're desiring a splash of color (maybe a peachy orange?)
I think what might get you the most usage from your closet is amt230's suggestion to install a second rod along one wall to hang shirts, skirts, etc from. You could then focus on obtaining uniform-looking hangers and evenly spacing longer-hanging clothes along the other wall's rod -- slacks, dresses, etc. (even a hanging sweater or shoe organizer)
Uniform size/color boxes for clothes or other items to be stored on the top shelves will help pull the whole thing together visually -- good luck!

Like everyone says, organization will make a world of difference. Also, once you have all of your blouses or short skirts in one location, you can use the space at the bottom for either a low chest or a double hanging rod. (I have one from the Container Store that I like, because I can adjust both the width and height.)

Other ideas include replacing the overhead light with a chandelier or thumbtacking a brown ribbon around the perimeter of the closet/shelf edges to resemble a trunk.

More than sweater shelves, sweater organizers! They are dividers that attach to the shelf and will keep your garments vertical.

Lastly, you may want a small stool to reach the items up above.

I have the same problem. A lot of the recommendations are really good (especially having at least one section of double bars...easy to to, give you lots more space) and uniform sweater bozes/hat boxes, and painting the dresser to match.

I also recommend you weed your closet frequently and put out of season clothing away (perhaps in large containers on the shelf...there's a lot of unused space between the shelf and the ceiling). Having less volume lets everything hang neater. Anything I don't wear frequently goes to the good will.

I do hang clothes by type. I wish I were motivated enough to do the color thing too, but just by type helps a lot.

If you have shoes on the floor, consider putting the ones you don't wear often (special occasion shoes, foul-weather boots, etc) in a basket or box on the floor.

I put a little inexpensive rug in my closet also...draws attention away from the clothes and makes it seem like more of a through-way.

I am reading this blog trying to get away from my closet reorganization! I have pulled out everything and it won't fit back in! I have a huge mess in my room but the closet looks great! I needed some inspiration so I went online to AT to "waste time" but I have been inspired to get back to work!

Use Huggable Hangers (available at Target) they are just perfect!

When I had a similar closet I hung curtains from the ceiling height to hide the clothes, added a cute little vintage side chair (useful when putting on shoes) and a lamp. Ended up looking more like a nice dressing room than closet