Ana has plans for a nice closet organizer. Something like that could make a good wall unit for storing lots of things, including your clothes.
There are also some nice designs around for storage units that incorporate a fold-out table. It's a desk and a table when you need it, hidden when you don't. Space around it is shelving.
Hanging wall cabinets are also nice. Ikea has some very nice designs, and Ana's designs for wall cabinets are a pretty good place to start.
One storage solution I like to use in small spaces is installing shelves around the top of the room. It is also a great way to add lighting! It is great for storage containers for items that are not used as often or for rotating seasonal clothing. I would have my sweaters up in the summer and summer clothes up in the winter.