Brought a friend visiting from Australia to visit Vegas....and when in Vegas, you need to do some cheesy tourist things like people watch and take a picture in front of the Las Vegas sign.
This place is like most landmarks - you see it, take a picture in front of it - either in a group or as a selfie and call it good.
There are some people who are photographers who will take your picture or if you take the picture at night, they will let you use their lighting equipment for a tip. Just use your camera or phone and snap away.