They wear formal dress, fix their hair neatly, and have the orchestra seating in perfect rows. They are projecting a sense of nobility, formality, and class. The signs for a classical concert are sharp clean and formal. The classical orchestra would never splatter their signs with mud, but a punk band might. Torn pants, bad hair, cords all over the stage, dented and bashed up equipment are all things that a punk band may do real well with.
Image is in the details.
Leave nothing unturned and set your own tone. Clark Suttle conducts Monterey Philharmonic. I would like to add at this point that a really good image rarely makes up for bad music. You still need to practice and practice hard. Of course we all know some exceptions to the rule where image did make up for bad music.