Everyone wants to have their work published. Before you submit your work remove all spelling and grammatical mistakes. If the publishers find mistakes in your work, especially in the beginning pages, they might conclude that the book requires more work than it is worth and they will reject it outright. If you submit unpolished work it will give the impression that you are an unprofessional author.
Go over your manuscript until you consider it perfect, then have as many people as possible read it because it is impossible for one person to catch EVERY mistake in a manuscript. Make sure you ask readers to be very critical of your work. Make necessary changes but make sure that you preserve your voice. Your voice is what makes your manuscript distinctly "you".