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!

Repaint understairs in white, the wallpaper doesnot work well and have your workstation under stairs

if u can forward your autocad file we can work on it

Dear Komal, Houzz is a promising platform full of many talented people. But to get any response for your query, you must provide them the proper information like- Location What you really want Built-up area if its Interior work Scope of the work like flooring, ceiling, furniture, wall paints etc. Floor plans if available Pictures of site if possible Only then professionals would be able to respond. Also you can check out my profile. Hope this helps you a bit. :)