First you want to get a square piece of paper. It doesn't have to be perfect, but it helps.
Fold the square down the middle.
Next, you want to fold the paper into a kite-like shape. Do this for both sides.
After that, flip it over to the other side. This time, you want to fold it only half way to the middle, but do that twice so it does reach the middle.
You can see that here.
Then you fold the small tip (the tip that's close to you) back. Do that again, but half way to the small tip side. This will create the head and neck.
After that, fold the entire thing in half. Pull our the head and neck, but not the body.
Finally, you unfold the body. If it can stand up on its own, you made it correctly. Mine didn't turn out too well, but you can practice to make it better. You know know how to make an origami swan!