Press passes are usually issued by law enforcement agencies, recognizing those accredited members of the media with an accompanying picture. Usually, your media organization applies to the appropriate agency to obtain a press pass. This press pass should be carried on your person -- like on a cord around your neck, or in a front shirt pocket -- at all times when you're working. The pass should be shown when you're trying to access a crime scene (your access will still be limited, but greater than that of the general public), gain admittance to a hearing or government affair, etc. Non-governmental entities also basically universally recognize government-issued press passes.
These agencies that issue press passes will also often issue news media placards for reporters' and photographers' automobiles. This comes in handy when you're trying to park at the scene of a crime or other news story; oftentimes, courthouses or other buildings will also have reserved parking for members of the media displaying the appropriate placards in cars.
If you don't have a press pass, go to Step Two!