I know nothing about flash but seeing as it's lashing down again outside I've been trying out the on-camera flash on my 60D and the 17-55mm 2.8 lens at various settings. And I did actually learn something, although not a lot. I wondered why I kept getting a dark half circle at the bottom of all my shots. Taking the lens hood off solved that one - partly. But then I discovered that even with the hood off you have to be careful of distance to subject and focal length. I hardly ever, if ever, use flash, but it was good to try. Got bored very quickly so this is about all I've done. A bit of my messy pencil box.
Have also been experimenting with the new cheap-as-chips MG3250 Canon printer but the photo prints are pants. As expected - it only cost £50, but the OH has a pro-printer so all is not lost.