Horror fiction

Some months ago I was around with friends. We were in town and it was raining slightly. One of us wanted to buy some CDs in a library which sells used books and disks. I guess it is the only such library in my hometown and I'm sure that's the only friend who still buys CDs. The library also sells books in English. Remembering my almost random choices in such a library in Toronto and how they turned out to be good choices, I bought three books, even though they were not what I usually like reading. In three or four days I read one of those three books: Ring, a novel by by Koji Suzuki. I finished it yesterday. Despite I didn't really like it, it was catchy. I wanted to know how the story developed and got to an end. In fact it does not end, but continues in two more books. I was so curious that I looked up online for the story and found that the book became a bestseller and that Suzuki wrote a number of sequels. Plus there where a few movies or series about the novels. 

I was surprised, since I didn't believe it was such a good book. The story looked too straightforward to me: the main characters have to figure out a curse and in the process they do not hit any dead end. Each step is a new clue which brings them towards a solution. I did not find depth in the characters or the facts - well, probably that's not the sort of fiction where to look for depth, but still.

Some points were clear in my mind at the end. If you want to write a successful horror novel:

• Go straight to your point, don't waste time with too many hints or dead ends for the story;
  
• Leave open details that you may use if you want to write a sequel. The story is like a puzzle too huge to be completed. You are putting together pieces of some areas and connecting those areas with tiny lines of pieces. Don't build all the borders! You can't build close to that part anymore, you can't write a sequel starting from there;
• Increase the rhythm as the story develops. Keep you readers glued to the book;
• Don't explain everything. Some air of mystery is necessary to keep things interesting. Unexplained or half-explained things may turn out very useful in the sequel, you may give them a totally new or different meaning;
• When things start to be sorted out and it looks like the story is going to finish soon, give it a twist. Make something unexpected happen and leave room to open up a new story.