So you have a brilliant plot for your book, but how do you write compelling dialogue?
Dialogue between characters is one of the biggest things that is going to keep readers interested, so it's best to spend time focusing on it.
The secret to writing good dialogue is conflict. You heard that right. Conflict keeps things exciting. Now conflict doesn't always have to be a big loud argument; conflict can be subtle, like a clash of personalities, a disagreement on what to do next, a difference of values, expressing fears. In every scene, try to have some form of conflict.
Now lets say, for example, you are writing a scene between two characters, and there is no call for conflict, then how do you keep it engaging? Make sure that it is crucial to furthering the plot. If it is non-essential to the story, throw it out. You might be thinking, well some fluff dialogue is good to get a sense of the character. Wrong. Often you can get a sense of the character by other means, other actions. If the dialogue does not advance the plot or cause some sort of conflict, consider cutting it out.
Another good test of knowing if the dialogue is exciting is by rereading it. If you can reread the scene repeatedly and it still is interesting, it is probably good dialogue. However, if you find yourself feeling bored with your own work, consider rewriting or trashing it.