This question has been rolling around in my head for a week, after my superintendent, Dr. James Merrill, asked it during our South West Area Kickoff (which was some really excellent PD).
There are three types of barriers I see for my students: social, personal and academic.
I try to remove social barriers by being really intentional about making all students feel welcome in my classroom. I want my kids to feel safe and included from the moment they come through the door, so I make it a point to post images that represent different cultures and points of view. This continues every time select artists to share - we have to include the diverse contemporary artists of today if we want our content to be relevant and accessible to our kids.
I also leave much of the walls empty. This is not a space I want to be a hommage to my art skills - it's for the community that we build together.
"It seems like you're having trouble following the rules today. Is everything okay?" always gets me further than "I'll see you at lunch detention."
All these things work together to make a classroom culture that's student centered, positive and empowering.