This isn’t math class. You aren’t graded on procedure. All anyone cares about is the finished product. There is no editor/agent/publisher who is going to reject your work because you didn’t make an outline and then write your story from word one chapter one to the last word in the last chapter.
I write scenes as they come to me, separating the scenes by large chunks of white space. I move the scenes around or sometimes I take them out. I write the end first and then pieces of the middle. Sometimes I have the perfect beginning and don’t know what the end will be until I write it. That’s what works for me and I’m not going to change it.
It’s great to know basics of writing and crafting a scene but it’s even better to know what works for you to get the job done. Your goal is to finish the book. If that means standing on your head and typing upside down, then do what you’ve got to do.
My favorite “white space” when I'm working? Picture it in bold, red type:
“INSERT SEX SCENE HERE”
Then move on to the next scene. And you can do something similar if you know what you want to put there, but the scene just isn't gelling for you yet.