I used to cut near my shoulders. That way I could wear short sleeves and they'd still be hidden. Also keep wounds clean and moisturized to help faster healing and to make the scars less visible. About your comment on blood stains, I'd recommend hydrogen peroxide on small areas, and then hand washing that area.
To get the blades, I used razors. You can take apart shaving razors easily and they make fairly deep cuts because of how sharp they are. Some get dull quickly, though, after 2-3 cuts
Hope I helped <3