CHILDREN'S authors are going to endless lengths to win readers back from the instant fun of video games and television cartoons. Action and humour that leap from the page seem basic ingredients for books aimed at today's six-to 12-year-olds. Blabber Mouth by Australian author Morris Gleitzman (Pan Macmillan $153) is one example. The book is written with all the pent-up verbal energy its wildly imaginative narrator can muster. But this isn't a comic book (as its cover unflatteringly suggests). The heroine, Rowena Batts, with ''knots in her guts the size of Tasmania'', cannot speak, though she talks endlessly in her head and with her hands. She is desperately embarrassed by her eccentric country-singing dad whom she loves like mad. The task before her is to come to terms with her new life in a normal school. Funny and touching. The Suitcase Kid by Jacqueline Wilson (Yearling $51) also mixes girls-own humour and extraordinary pathos. This time the narrator, a 10-year-old called Andy, is faced with the divorce of her parents and life as the suitcase kid living between two households. Easy as ABC? Only when she gets to the letter Z for Zoe, her new half-sister, and after having befriended an elderly couple who own a mulberry tree like the one in the home she has lost. This sensitive, candid and funny book should bring comfort to the large number of children sharing Andy's situation. There is plenty of fun for new readers in Nora Bone by Brough Girling and Tony Blundell (Jets $51). Nora is a wayward police dog whose hour as a heroine comes during a school fete. The simple story is made extra special by words that literally loop roundthe pages and wacky cartoon pictures to match. Popular vet James Herriot's Smudge's Day Out, (Picture Piper $68) is a tear-jerker for pre-school children. In this picture book, illustrated by Ruth Brown, Smudge the lamb finds the grass on the other side of the fence is not so green. After making his escape he is terrified by first a dog, then a bull and cannot find his way back to his mother. However, help is at hand, making this a gentle introduction to the hazards of the world we live in.