When you begin writing a book, especially if you write science fiction, horror, fantasy, paranormal romance, or the like, there are several things you must watch out for. First, you should familiarize yourself with what's already been done in your field. You need to avoid cliches and plots that have been done to death. Too many cliches can make your book downright laughable. Unless you are deliberately going for comedy, do your homework before you start writing.
There are other obvious things to avoid. For instance, if your vampire hero looks, sounds, and acts like Edward Cullen, you are going to be accused of copy-catting, even if you haven't! Here's an example from my own experience. For many years I've been kicking around an idea for a fantasy novel. I've found that naming my characters helps in plot development. So I named one of my main characters Trueblood. Errgh!
You can probably see why I was forced to rename him. His name became Gray. Uh-oh! Holy Toledo, Batman! Now I have to change his name again!
This time I think I'll wait until the last minute to christen this poor guy! Maybe I'll come up with a name that will be original and not appear to be copied from another source. I may have to name him Rzl-t'plk.
I'm not the only author who has stumbled into predicaments like this. When you come right down to it, the best we authors can do is try to be as original as possible, keep our eyes open, and keep our fingers crossed. I guess there are worse things than being accused of mimicking another author's work,
Keep on reading and for heaven's sake keep on writing!