This was originally going to be a lengthy list. It was going to be a big list of all the things that people traditionally do wrong in time travel movies and books.
Unfortunately, it started out like:
...and so on and so forth. The more I thought about it, the more I realised that because unless something goes wrong during time travel, you don't HAVE a book/movie, and that therefore there is only one real rule which is
Do not travel through time for any reason
That is all.