It depends on if you want it to be dorm comfy or to look like you're not in a dorm room. The former is pretty easy to do and can be done on a student budget. The latter is much harder to do and best saved for Target and Ikea ads.
You can give it the college try and cover your place in textiles. Generally the burning of patchouli or posters of Bob Marley fit really well with this.
Ha, I'm kidding, but you get the picture. Sheets, curtains, rugs, bedspreads, and yes, the pillows can really personalize your space.
I'm a big fan of textiles. Plus you can take them with you.
Kmart, Target, all those budget stores can supply them. So can second hand stores, dollar stores, etc.
I know on my college campus, posters were very popular and cheap.
My dorm room always looked like a dorm room, but it was very comfy and cheery.
My guess would be posters/pictures of things you like and such mainly. Also, perhaps decorative wreaths, plants, vases, etc? You don't want to do anything irreparable/expensive to the room since it doesn't belong to you.
It really depends on whether they allow nail holes to be made or not as to what you can do.
In a small space it's important not to have too much clutter so look for great closed storage pieces and multi-purpose items.
Not trying to be your mom here but please keep at least a 12" free area around any candles. They can be a hazard in small spaces.
Good point. They can also add soot to the ceilings or walls.
Ikea is inexpensive and used by many. If you want to add personality to your room, visit the thrift stores for unique "collectible" items, like a planter, clock or other desk accessories and artwork that will add dimension to your room.