I would brighten it up by painting the walls a more neutral color. Adding new bedding and fun pillows, artwork, etc. will add punches of color that will work nicely with the neutral backdrop. As a student I know designing in a budget friendly way is important. If you have an Ikea, HomeGoods, Gordmans or At Home to shop at, these are all great places to pick up interesting and fun pieces without breaking the bank. As far as space planning, from the picture it looks like a fairly long/narrow space- I would keep the bed at the back, back a sofa up to that and add a couple of comfy chairs and maybe an area rug. Dont forget the artwork too, this adds a very important layer to your space. Hope this makes sense and helps!