Does your story “taste” good? In a fantasy/sci-fi world, have you worked out what your characters eat and how they do it? How is their government run? Even if that is not a major element to your tale, there should still be some indication of what it is as that helps make your world seem real. A “tasty” story leaves no loose ends but should make you wonder what happens to the characters after that finish. Is the tale something you can envisage happening to someone in some universe somewhere? Use the senses. Jilly Cooper is a great advocate of the use of colour to bring scenes to life but use all the senses. We do. Why should your characters not do so? An odd sentence here or there is enough to add colour to your story in this regard.
Character Crises
What brings your character to the crisis in their life that forms the basis of your tale? Don’t put in a huge block of narrative to explain this, drip feed the information, but the stronger the character, the greater the crisis they can face. A stubborn person can create more crises for themselves than a passive one. And are your characters distinguished enough from one another to stand out?
Twists and Turns
Whilst your story, particularly novels, should have twists and turns, it must still end up somewhere. Does your ending have punch? Don’t let your tale peter out. Are you keeping your readers guessing? Twists and turns shouldn’t be obvious. Part of the fun of reading is trying to second guess the author and not always guessing correctly!
Character Achievements
Does your character know what they must achieve? Do they care enough? If they don’t, your readers won’t care either and your story will sag. Is your character doing everything they can to get to that point? Commitment from the reader demands commitment from the character/author in the first place.