My daughter (aged 8) tries writing stories. She makes lot of spelling and grammar mistakes and always has a dearth of topics. How can I help her to continue her hobby?

wow that is really wonderful. in fact, my 9 year old also loves to write down stories and poems and keeps doing that almost all of her free time. whenever your daughter comes up with something, encourage her to write it down. she may do a lot of spelling mistakes and grammatical errors, but all it means is that she is so busy in her storytelling that she is not able to focus on those points for the moment. i don't think you should worry about it. get her a pretty notebook that she can use for her writing and can carry around with her to use whenever the stories come up in her mind.