Can you show your commitment to your art? That is can you show you take out subscriptions to the professional mags, regularly read editoral and publishing blogs, you regularly enter writing competitions and ideally have had one or two things at least published.
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!
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.
Do you know in which direction your story is going in? Any tangents off the main plot should be ones you want, not ones you accidentally get into.
Have a list of things to do, deadlines to meet, it keeps your writing varied and meeting deadlines is always good practice. It is what professionals do after all.
I write scenes I “see” in my head, very much like seeing your own film. Dialogue is what I “hear”, what I could hear on the radio for example. Doing this can help keep what you write realistic. There’s no place for the “herebefores” and “whatsoevers” now!
Remember Jane Austen still sells well now because (a) her plots are good, (b) her characters are good and (c) she doesn’t use archaic language. Yes her style of prose is longer than we use now but that’s because she’s a classic writer. Those of us writing now can’t get away with that! You’re writing to people who speak in modern language, write in the same and want to read stories written in that style.