To get blood out of clothes, run the article under cold water, as hot water will set the stain. Peroxide is effective at removing blood stains, but it works best when applied right away. You can also use an enzyme stain remover. Scrub the stain well. Make sure to wash in cold water, and hang to dry.
The best luck I've had getting blood out of clothes was to run the clothing under cold water right away. But then, I'm talking about a small amount of blood. I would also suggest scrubbing the area with regular bar soap and an old toothbrush. It actually worked! Try it.