We are all in love with our scripts and may have difficulty thinking clearly when in the emotionally-charged state of wanting to consummate our relationship with our script by selling it now. Don't be rigidly tied to your plot Time and again, I see writers who create their dream plot and then contrive everything else to fit that plot structure. In that state of mind, it becomes difficult to be creative because everything must serve the plot. You are hindering your own creative process. Once you see problems you need to solve, be flexible in your solutions.
Nothing is sacred.
Don't be afraid of throwing out scenes, changing motivations, combining characters, and so on. The single-most helpful key to the best revision lies within yourself. When we are honest with ourselves, we get a feeling that something works or something doesn't. We may not know intellectually exactly what the problem is, but there is something silently nagging at us from inside. This voice of truth is not an emotion.