When walking anywhere in public, i automatically put on my best poker face. I set my shoulders & walk with confidence. It's hard to do sometimes, but it makes me seem unapproachable, so i don't have to deal with talking to people. Which scares me.
Edit: I'm usually listening to some form of music, & that helps me clear my head a bit. When i get too nervous to maintain my composure, i walk as fast as possible, avoid eye contact (not that i wasn't doing that to begin with), & dodge/weave through the people.