Do it more.

It's really the only way. Take headphones, listen to podcasts, or music, or Audiobooks. Take a book with you (or an ereader, or get an ereader app on your phone to save bringing an extra item)

Just remember, 99.9% of the people you see won't even really see your face, let alone remember anything about you in five minutes time (unless you're doing/wearing something really outlandish)