Before you start the contest/ submissions/ conference circuit ask yourself this one little question.
Am I truly happy with my work or am I simply ready to move on?
For the love of grief, make sure you answer the former before you begin the submission process. Why, you may ask. Well you know me, I have an answer for all questions, even if it's a snarky one. First, why would an editor or agent or even the host of a contest pick your work over someone who is happy? Let me tell you folks, if you haven't been there yet, those rejections sting like a mother, so make sure it isn't due to the quality of the submission.
Does your plot make sense? Has the main conflict been resolved? Does your hero/heroine break out of his/her shells to save the day/town/world/universe, or just stop acting like a big old tool and behave like a quality human being? A little resolution is necessary or the reader will not be coming back.
Did you use your words, kiddies? Both to paint a vivid picture and to evoke emotion from the reader. You're biased, so you don't count. Get yourself a beta reader, someone who will tell you if what you have written makes sense.
How's your grammar/spelling/punctuation. Mine suck. I have a homonym dysfunction. I work VERY hard to bring my manuscripts up to snuff and believe me when I say, it gets easier, but you have to do the time. Use sites like autocrit or invest the time to bettering your craft. Words and language are the tools of your trade, all the skill in the world won't turn a block of marble into a statue if the artist doesn't have the tools for the gig.
If you are not satisfied and submit anyhow, figuring "that's what an editor's for" have someone you love smack you upside the head, from me. Then go back and read writing commandment #9. All you've done is add to someone's slush pile. They will not thank you for it, and neither will the serious writers who actually do a little non government sponsored quality control. Does the manuscript need to be perfect? No. Does it have to look like someone with more than a third grade education penned it. Might help.
If you have doubts, stow it and move on for now. Do not settle for self publishing/ vanity press or an author mill. Trust me folks, it's not worth the aggravation to see your name in print. It all comes down to your ultimate goals and ambitions. Where do you want your writing to take you? What's the long term plan. Was finish a book and hand it out to friends it? Try lulu.com, they work well for that purpose. Make some money, well that'll be our next set of commandments.