I'm told my SF is of the hard variety and my Fantasy is romantic but hopefully all the characters are strong and the plots are lively.
I describe my plots as follows; A character is walking down the street when all of a sudden a piano falls on them. They spend the rest of the story digging out from under that piano. How they dig, how long and how well, this all depends entirely on the character.
I think people enjoy a series. When you like a story, many readers want more of the same, which is dandy, if the author and the characters have more to say.
If I get blocked, it is generally because I don't know enough about some aspect of the story or the characters. The answer for this is generally more research, or making more background notes, so the place and person can be more fully realized inside my own mind.