When you're finding those bugs or slips in your plot and need a quick repair or a lengthy one, Here are some things to remember.
1. Your plot line. Man against man, Man against nature or man against himself. Oneof these should be the major theme underlining your story.
2. The six elements.- Wo, what, when, where, why and how. Is each one developed to the max?
3. The nine areas should be examined, Framework, motivations, significant events, the vital idea, the action, the reactions, the goals, the sub-plots, the conflicts both the internal and the external.
Acrually, you could plan your next book while keeping all these in mind.