An associate who is a top-notch journalist told me not long ago, "I still love to get bright sparkly 8 x 10 photos in press kits. It gives me an idea of who the person is you're asking me to write about." Photos really are worth a 1000 words and saves the journalist much time in describing who they are writing about. Each of us make instant decisions based on thousands of images we see every day. The average person is exposed to 10,000 images daily.
For your press photos you need to take some time and make your image stand out rather than blend in with the other 9,999 instantly forgettable impressions. One way to accomplish this is to look at fashion magazines. Use the experience of set designers, photographers, make-up experts, hair stylists, and other industry experts who craft memorable images every day.
It's true the advertising industry has sold us on the idea "sex sells." This is particularly true for women. But I'd argue that allure sells more than sex. If sex is what you're promoting then by all means have at it. But I'd take a more demure approach and fashion your look within the premise of your product.
Locate and interview at least three professional photographers before a knee-jerk reaction overshadows your better judgment in hiring your boss's daughter to take your photos.
Make sure the photographer can offer you high resolution hard copies as well as formatted jpgs in color and B&W. Schedule time to take at least 100 photos indoors and out; that include full body shots as well as the ubiquitous headshot.
You shouldn't buy a new wardrobe for a photoshoot. A good photographer will always have props and wardrobe alternatives on hand during a shoot. The object is not necessarily the outfit, but make sure you dress your part. Don't underdress or overdress for photos. Choose interesting colors for your skin tone. Choose interesting types of clothing that enhance your body type. For headshots wear interesting jackets, sweaters, or other garments that enhance your personality creating an image you are proud of.
If makeup happens to be part of your image don't overdo it! If hooker, or skank is part of your act that's okay if you want to get booked into strip joints. Yes, I know Lady Gaga does it...but she is Lady Gaga and it's likely part of her contract.
To become comfortable in front of the camera do informal practice sessions at home. Unless you are naturally photogenic it takes a bit of practice being in front of a lens. If you come up with some interesting ideas make sure to show them to your photographer.
Location, location, location is truly important. If you're a concert hall artist, a construction site for your press photos is a really bad decision. While lots of people use that option, what highbrow music organization will reproduce a construction site photo in their series marketing materials? I truly understand the concept of artistic juxtaposition, but give considerable thought to the end user in all details of your photo shoots.
My parting shot: Always make sure the photogragher is credited on the 8 x 10 glossies. If you send formatted jpgs to the press always include that credit as well as the names of everyone in the photo from left to right.