SFGate

INSIDEOUT Modern and Traditional Hi L, one option would be to revel in a trend and go hyper stylized. For example, a trend is neon colors therefore, you could paint your furniture in a neon color (eith pick one neon plus black and white or pick a few neon colors). Wood, plastic, metal, old framed art, accessories, etc could all be painted. Alternatively, you two could decide to go Woodland Glam with wood, gold, silver and white. I hope this makes sense! Best, Diane

househaunted I assume you're both college kids on a budget. Eclectic / boho/ hippie-esque style is one way to go: where there is a randomness to everything, but colors, etc... are used to pull the whole thing together.

Ideabook: How to Savor Your Beautifully Imperfect Home

I would use some good size pillows on your couch. The fabrics can have varying colors, patterns, as long as they complement the couch and each other. Also they'll add comfort and are practical.

I would use your fridge as a big backdrop for pictures, schedules / photos--like you already have, but I would use the whole fridge / artfully arranged of course. Make sure it won't be a hassle to clean when it's time to leave though.

Kitchen

See also that they display fruit / vegetables in this kitchen as a source of color and hominess.

Multi-colored rag rugs are pretty and inexpensive. I would get a rug pad and buy one for the kitchen. Possibly a large one for the living room with a rug pad underneath.

One large picture or lots of varied size picture over the couch:

Living Room 1

Colorful Cottage

Nina van de Goor's Home

Living Room 2

You could do the same for the hallway, hang photos, pictures.

Maybe hang some of these led icicle lights along the wall in the dark hallway. I like that these have a "warm" light and shouldn't look harsh, get hot, or be expensive to run:

Warm White LED Icicle Lights

I would hang some gauzy, light filtering curtains in the living room window under the heavy drapery and keep the drapery pulled back during the day, and closed for privacy at night.

Ideabook: Street Smart: Inspired Bohemian-Style Curtains

Plants add a lot to a room too:

Living room

Carolyn Albert-Kincl Design At the end of your entry hall, I would hang a drapery panel hung from a tension rod, floor to ceiling. You can then place the piece of furniture in front of the drapery. A tension rod does not require holes in the wall.

judyg Lots and lots of mirrors. Scour all the resale shops downtown, and as suggested above you could paint the frames in high-gloss colors.

Lighting, both on the floor, like this inexpensive corner light and/or uplighting to call attention to the tin ceilings.

bygeorgi Hallway -I see that hallway is really the problem , replace that small dark piece with a tall white bookcase, I suggest Target for that , it's about $30. You can make it a bit cuter by adding fabric or even wrapping paper to the back piece before assembling it. Then buy some thrift store art or repaint your own art on them .. make sure they are large and light in color, you can also hang a mirror to reflect the ceiling light.
Living room- an inexpensive one- size fits all slip cover for the sofa and paint on your table and chairs in front of the window, use that grey curtain color for other things in the room, maybe the coffee table ,graphic pillows, add with a funky vase and flowers, stack of books ....
Kitchen- its cute, paint the bistro set in a color you use from the living room add some art and colorful kitchen accessories
For an inexpensive piece of art I suggest take that nice picture of you two and and have an "engineers print" made, places like kinkos do it and it's super cheap like $11 and its huge! but it is only black and white , spray mount it onto an old canvas or even poster board. And hang funky old thrift store or flea market mirrors up where ever , they will add light and a fun look..

Karen Tiede Art Rugs +1 for mirrors, and look at hanging them in the adjoining rooms, if you can, to reflect more light into the hallway. We get huge mirrors out of new subdivisions from CraigsList; takes a big truck. You can get a million more bargains if you have a friend with a truck.

Incidentally, Sam's Club has a new battery-operated motion detector lamp that I love in my un-wired hallway. Comes on instantly and goes off quickly. The light's a bit cold (LED) but it solves the dark-hallway, arms-full problem wonderfully. I think they were $14.95 for a pack of two.

decoenthusiaste Go to a fabric store and rummage through the remnant bolts on sale. Pick a colorful one and get a decorative curtain rod and a wooden dowel, some iron on product called Stitch Witch. Make a rod pocket on each end of a length of fabric measured to cover your wall as you wish. Hang the fabric on the rod (weight it with the dowel on the other end) at the end of your entry.

groveraxle A collection of funky thrift store mirrors over the sofa will reflect more light.
Time Worn Style ~ Stair well

If you don't need the privacy, get rid of those heavy drapes and replace them with something gauzy. Lightweight burlap hung with curtain clips would be inexpensive and airy.
Watch Hill Rhode Island Residence
The Old Painted Cottage

If you have an Urban Outfitters nearby, check them out. They have lots of inexpensive products perfect for a college apartment.
http://www.houzz.com/photos/users/urbanoutfitters

cohoek I take it you could change the curtains? What about nice thick white curtains? Is the furniture yours to paint? You could paint or stain only the legs of the coffee table white, and sand down the top and leave it wood, paint/stain the chairs white and cover the seats with material that fits with the couch. Do the same with the dining table, I 'm not a fan of painting the tops white, they get ugly really fast, google riviera maison for ideas, I take it it would be too expensive to change the color of the couch? A linnen colored slipcover would look fantastic...About the kitchen, you can put a piece of fabric in a light blue over the fridge to toon the white down a bit. and buy a vinyl tablecloth in a blue and white checker, they're all the rage here in Holland. Put lots of blue in the kitchen too. At the end of the hall you could make a big board by taking some softboard and stapeling a piece of fabric around it, use it as a bulletin board or hang a smaller picture in the middle of it. You could do alot of these in the hall, or just go thru it real fast and sit with friends. Light blue and bruin are very beautiful together. Try and learn! We have an ikea here to buy cheap accessories, my daughters go wild...