Blood on the page/screen

Why is it that the more I learn and supposedly understand about screenwriting, the worse I get at putting it into practice?
A friend recently sent me a link to an episode of Charlie Brooker's Screenwipe. Usually these are sort of parodies of the nature of television but in this episode it's a discussion with the writers of various UK TV shows. One of them describes writing as bleeding onto the page, which seems about right.

I've been reading a lot of things from the scriptlab and various other random links trying to find ways of streamlining the story I have.

http://thescriptlab.com/screenwriting-101/screenwriting/script-tips/653-writing-the-smart-short-film

http://thescriptlab.com/screenwriting/script-tips/436-the-character-driven-story

http://thescriptlab.com/features/screenwriting-101/3375-story-equation-expanded-applying-the-four-variables

Essentially all of the stuff I thought was good, is the stuff I'm going to have to pull out. It's all of that symbolic theme-y stuff, I can't seem to keep that while keeping the story moving. I've got all of these separate elements pulling in different directions.