All promotional pictures can be taken in the same manner as a glossy, with additionals sizes, to the 8X10 being available.
Posters which are created to promote a show should ALWAYS include the following-club name and location, cover charge, minimum age for admitance, and the other bands on the bill. Very often people won't go to a show if they think only one band they like is on the bill, so its important to let people know who else is playing that show.
It goes without saying that your promo posters should be attention getting. There are several ways to go about this, the L.A. hair metal bands made eye catching flyers and posters by necessity.
The acid green color which is still associated with Poison was picked early in their career because it was the cheapest color paper to print on.
If money isn't that much of a concern, or neon colors just don't help to create the image you were going for, then it may be a good idea to enlist the help of a local artist.
Many up and coming painters and illustrators are also looking for greater exposuer and would welcome the chance to have have it be on display.
Craig's List is an excellent place to place an add looking for such an artist.
It is also a good idea to speak to your friends, and have them sketch up a few images. We here at The Music Snob had our logo designed by a friend.