Today I'd like to talk about proofreading your work. It's very, very important that you do this thoroughly before you get it into the hands of an editor. An instance here and there of a misspelled word might be excusable. Repeated instances of misspellings, sentence fragments, and punctuation errors are frowned upon. They might convey to the editor that you haven't completely proofread your work before handing it in, and (worst case scenario) that you expect him (or her) to pick up the proofreading slack. This could result in a manuscript rejection, which none of us wants. It's frustrating for all parties involved.
While editors back in the heyday may have been able to give much more personalized attention in line edits and basic structure, remember that these days it is your job to catch all these minor errors before it even gets into the hands of a professional. You'll get much more out of your editor when she's able to focus on content, rather than structure. She can help you develop and deepen your characters and conflicts--but only if she can see past the structure of your writing itself. So remember to run a spellcheck, and do a thorough read with an eye to sentence structure, punctuation, and grammar use. Your editor will thank you, and when you're that much closer to publication, you can give yourself a big ol' pat on the back.