You just fucking write it.
No, seriously. This is hard. Instead of blogging right now, I should be working on Undead Again. I have the file open in another window and it's glaring at me. It's begging me to finish it and I really want to, but it's so difficult. People who don't write used to think I was crazy for going home after school and pounding out 50 pages or more.
"Why are you doing all that work?" They'd ask. And I was like...what work? I'm having fun. I'm making up stories. What did you do all night? Jerk off? Yeah...thought so.
But back then it was easier. I could write the worst story ever and be proud of it because I made it. I'm not naive though, I knew my stories were bad. I knew that the characters were flat and that story dragged in places but it didn't matter. What mattered is that I made something all by myself.
Now I'm in the big leagues. I can't just churn out garbage so when I write a sentence that doesn't seem right, I scrutinize it to hell. No story is perfect. Everything has some kind of flaw, but it's not wrong to strive for perfection. My goal is to be get a little better each day. Over time, I want to grow and be able to look back and measure my growth.
If you could read some of the stuff I wrote as a teenager, you'd laugh your ass off. The stories were ridiculous and my choices of words and description were just plain dumb. However, I will never get rid of those stories. I was even thinking about getting copies so I can show people. It would be fun to laugh at myself.
You can look up all the articles you want about rewrites and how to do a second draft and how to fix this or that...but it all comes down to you. Only you can fix what's wrong. The best advice I've heard was listen to yourself. Trust your gut. If you feel that something isn't working, change it. If you trust your instincts, they'll never lead you down the wrong path.