"The first draft of anything is shit"
Once the first draft is finished different writers do very different things. Some throw the manuscript into a drawer for months and sometimes a year and then go back to it. I have done this once, and when I came to read it again I fell into a deep depression when I realised my amazing "work of art" was complete crap. It had massive problems with all the elements that you absolutely have to get right like...character, structure, tension, resolution and plot. So I deleted three quarters of it and started again. I don't reccommend that.
I think I should have just kept going because I lost the magic place I was in when I was writing the book in the first place. I started getting self conscious in my writing and worrying about people reading it and once you do that your creativity is compromised. I know not to do that ever again. Now, when I finish my first draft I celebrate, I cry, I jump up and down. I excitedly tell everyone and freak out when they want to read it and get straight into the rewrite.