That is as true for fiction or non-fiction. The writer has to really know their subject. It is really important to remember that the readers are a lot smarter than the writer. Also, good writing has to do with rewriting. You will never get it right the first time. So you rewrite and rewrite again until you get it right. Until you, and the reader, will be able to visualize what you're writing about.

Some writing courses will advise you to write what you know. I've always thought this is very odd advice ... because it means, for example, that I should not be writing about Nicholas Flamel, because I didn't live in France in the 15th Century, I was not an alchemyst, am not immortal (despite the rumours) and do not know magic.

Making sure that the geography and timelines work is always the hardest part of writing. But you owe it to the readers to get it right!

The research. It is always the best part of writing. And, of course, it is the great excuse to travel.

I am a great believer that all the primary research has to be done before principle writing begins. I'm a huge advocate of plotting.

I am of the generation of writers who can get instant feedback from readers within hours of publication. The fan forum is extraordinary - readers from all over the world coming together to discuss, argue and debate scenes and characters from a novel. They add a layer to the story that I cannot write and yes, I will participate in that conversation and answer questions. After all, they are the people I'm writing for and their enthusiasm and questions really pushes me to raise the bar.

My advice is to write about what you are interested in. If you read science fiction and fantasy, then write in that genre. If you read romance novels, then try writing one.