I've rediscovered the mini-courses at BBC GetWriting (I used to be a member of the GetWriting community but it closed down a few years ago) and there's some really useful articles there. Go here:
and make sure you click on the 'read text only version' rather than the Flash version (the flash version is bit tempramental).
I've also ploughed through the archives of a blog called "Diary of an Unpublished Author" (which is a misnomer as she's going to be published very soon). Check it out here:
Some useful links and info here:
And a very interesting article about writing fiction for 8-12 year olds here (pdf format):