Another thing my mum taught me and my sister is that a little blood goes a long way - especially if mixed with water or on damp skin. I remember an incident when I was about 7 years old, when someone caught their fingers in a sash cord window (sash cord failed when their hand was under it), and dripped blood into a sink of water - it looked like the whole sink was full of water, so after dealing with the casualty, she took as tiny bit of the bloody water, added it to a glass of water, which looked like all blood. Living in a small village, people quite often came round to our house, with the after effects of farm / garden accidents / animal bites etc, so we got quite used to it. We moved to the outskirts of a city when I was 9, so far less blood after that! Although we still needed to help occasionally, such as when a neighbour put arm through glass window, so someone came to fetch Mum to their house.
Not trying to be gorey - the main point is that you need to know what to do, as there's no time to read a book when faced with a bleeding or unbreathing casualty.