Hello Cricket,
this varies depending on the age of the stain. For a fresh blood stain, rinse with cold water while rubbing the stained portion against itself to loosen the excess. Wring the item and apply hydrogen peroxide to the stain. Allow to sit until it dries then launder as usual. If that fails to remove the stain, or if it's an older stain, rinse with cold water, gradually scrub the stain with a mixture 2 parts salt to 1 part dish soap, rinse again with cold water and launder. A burn or scorch mark will weaken fabric. Soak immediately in cold water at least overnight or up to a day. Wet a clean cloth with peroxide and place it on the burn. Iron on low heat, moving the cloth as the scorched particles detach. Rinse with cold water and launder.
Alternatively, a white vinegar or lemon juice soak may be used for either of these issues. Allow a soak to sit on the stain in direct sunlight to bleach before laundering. Bleach or OxyClean also typically work for such stains.