You've finished your manuscript. It is fantastic! You can't wait to send it to every applicable agent, convinced they will pound down your door for a full. Even though you think you're ready, the sad truth is, you're probably not. I'm a firm believer in nonconformity. I go with what makes sense to me; however, in this one tiny instance, I'm going with the crowd. This is the time to utilize use your beta readers, high school/college English teachers, or even just close friends who will review a copy of your work. Ask them for specifics. To highlight: a) every time an action is told instead of shown, b) repetition of words and actions, c) setting descriptions that are weak, d) areas of confusion...etc. Anything that slows them down or lacks substance. This will help you identify areas that could use a little extra polish and those that need elbow grease before the polish is applied. Most likely, you will only get one chance to submit to an agent. Why spend so much time on your manuscript, if you're not going to spend that extra time perfecting it.