Yesterday I wrote a little bit about the benefits of attending and participating in a writing critique group, but I'm not sure I adequately described just how important it is to have another set of eyes read a manuscript before sending it out before being considered for publication.
Even the most polished manuscripts could be improved by the critique of another reader. Other writers understand your goals and can help guide you through the process of the writing and revising your manuscript. And each reader notices something else that can help you improve and strengthen your work. When critiquers start noticing the same thing, you know that they've hit on an important point that needs to be addressed. But even if they are not all in agreement, writers can benefit greatly from taking the advice of those readers who have experience writing and publishing.
So try it! Find a supportive group of people whose opinions you trust.