Because each dorm is going to be a different size, with different furniture and features, some of these hints will be less useful than others. But there are some fairly universal features between rooms, so hopefully something will help you out.
Before you head off, see what you have to work with. Many colleges will tell you online how big dorms in each building are, and what furnishings you will be given. If they don't, call or e-mail and ask. Before you get there, have a rough idea of where things may go, but be flexible. Your roommate will have their own stuff, and their own idea about how the room should be organized.
The key to fitting all your stuff in our alloted space is organizers. Extra shelves, drawers, and boxes will be your saviors.
1. Boxes under your bed.
They don't need to be the fancy ones with wheels on the bottom. They don't even need to be plastic; most college computer labs will let you take the cardboard boxes that printer paper comes in, and if not you can buy them for $1-2 a piece. Under your bed will be your "deep storage" space; where you put your luggage, seasonal items, and pretty much anything you won't need on a day-to-day basis. Put the stuff you only need once or twice a term at the very back, near the wall, and things that you'll need to keep more accessible towards the front.
2. LOTS AND LOTS OF CLOTHES HANGERS
I came to college with 2 dozen, thinking that would be plenty. I now have 45, and could probably use another dozen or so. Hanging up your clothes saves tons of space in your dresser drawers (if you even get a dresser) and it means you never have to dig through to get that shirt at the very bottom of the drawer.
3. Shoe Organizer
I'm a girl, and I have lots of shoes. That's kind of how it goes. In addition, I'm on the ballroom dancing team, and I have four extra pairs of shoes for that. That's a lot of shoes, and I use the floor of my closet already for my laundry baskets. Getting one of those hinging shoe organizers was SOOOOO helpful. You can make one yourself with some fabric and dowels, but when I found one on sale at the container store for $10, I said why bother. It has 10 slots for shoes, but if you have skinny shoes like sandals, you can fit 2 pairs in. If you would rather have that hanging space for clothes, the racks that sit on your closet floor also work great.
4. Laundry Hampers
Have multiple hampers for the different loads that you do. My hampers are just the right size so that when one is almost filled up, it's a full load of laundry. Also, if you're the sort of person who doesn't put their clothes away right after they're washed, or who wears clothes multiple times before washing, having an extra hamper for clean clothes that need to be put away is a good idea.
You also don't need to use them for laundry. Pretty much anything can go into them.
5. Hanging organizers
There is a great variety of hanging or over-the-door organizers for all the small, random crap that you accumulate. Put them on pretty much every door in the room. having different kinds lets you store a wide variety of things this way. These are also quite easy to make, either by sewing or with a glue gun.
6. Shelves or Drawers
These are great for books, clothes, your stash of food, pretty much anything If possible, get the kind of shelves where you can adjust the height of each shelf, or drawers with a variety of sizes, again so you can store a wide variety of things.