You should be ready at all times to promote your band and a press kit is one of the best ways to do so. Generally, a press kit consists of:

A Cover or Briefcase: Some people just use a folder and others use a briefcase or something large enough to hold CDs or DVDs. If you use a folder, include a cover with your band logo or some other eye-catching device.

Contact Information: Keep a contact page available that gives your contact information, along with a little information about the band, such as the style of music.

Booking Information: Similar to the contact information but small enough to include with CDs, a sticker or perhaps a business card.

Artist Bio Page or Intro Page: A basic introduction of the band, including the style of music, information about the members and location of past performances. In addition to band member bios, relate if you have your own sound or light crew.

Promotional Material: The way to secure future work is simply to make the venue money. Let the venue know how you plan to promote an event. You can do so by building up your fan base, putting up flyers, handing out demos, or whatever you have to do to get people to a show. Keeping sample flyers and such with your kit is a great way of showing the venue how you plan to advertise.

Band Pictures: Keep quality prints and electronic images on hand for promotional purposes.

Equipment List: Put together a list of the equipment you have available for gigs, including information on whether you have your own sound people. Include detailed information like the wattage of your amps, light equipment and so on.

Demo CD or DVD: Make you demos look and sound as professional as possible. Make sure you use your best material and don't forget to include your contact information with the CD.

Song List: Include a list of all of your original work as well as cover songs you play.

Newspaper Clippings / Reviews/ Articles: Keep a collection of media copy that relates to your band.

Business Cards: Include your contact information and logo. Keep them on you at all times; you never know when you might meet someone that can get you work.

Envelope/Folder: A small press package to hand out, include contact information, band bio, images, equipment and song lists, a demo CD and business cards.

Beyond a press kit, it's also a good idea to keep an updated webpage with music samples, contact information and a calendar of upcoming shows. Many bands also send out newsletters to their fan's email address to let them know about their upcoming concerts and events.