Dictionaries define the word edit as "to prepare for publication" and "to cut or eliminate". In order to edit one's own work one must learn to do both. The cut or eliminate part can be difficult for beginning writers as we worked so hard over our choice of words; lovingly cataloging all the details of a scene, providing vignettes to disclose our characters back stories, sweating the sentence structure, honing our verbs. It can be very difficult to look dispassionately at our work and ask, "How much of what I’ve written is vital to the story?" Time and experience helps, but few writers are ever their best editors. That's why it's a separate profession. We need them. We can and should learn how to edit our work however, even if it's an imperfect edit. Most beginning writers overwrite their scenes. Too many details, side stories, clauses, adjectives, words. A good exercise to begin with is to look at something you’ve written in the past (the older the better) and see how many words you can cut out and still leave the sense of the story/scene. For example: "John was a big man, carrying an extra hundred pounds" could be reduced to "John was fat." Or "That morning they left the house at ten and drove the two hours to San Diego" could become, "They arrived in San Diego at noon." The important thing is to start making judgments about what should and shouldn't be included in the finished work. One of the hardest--and most essential--skills for writers to develop is knowing when to hit DELETE.