Dani,I used to write a music column for a mid-size daily and I've been an editor for a lot of years, so I'll comment a bit on GtD's post above and try to add a little to it.
First, he's right — a lot of copy editors are lazy and/or grossly overworked, so they don't like things they have to work on a lot. Which makes for two definite no-nos.
1) Don't over-write. Get to the "Who, what, when and where" quickly — the journalistic "why" isn't necessary when you're talking about music unless the event is a charity fundraiser or some such. GtD's also right about the "inverted pyramid" style of writing. The most important information goes up top, then "cuttable" details can follow, from most to least important. That way an editor can just cut where it's necessary.
2) Don't be overly effusive in your praise of the subject. It's a sure sign of an amateur and editors HATE it. Analogies are OK, as are comparisons to well-known performers — describe her voice as being like "Emmylou Harris with turbo" or having a "soaring, Baez-like delivery" or whatever is appropriate — remember, y ou're trying to describe a SOUND to someone who's never heard it. You have to give them an anchor.
But again, keep it short.
3) Include career highlights — major venues she's played, awards she's won, CDs, songs made popular by others, etc.
4) GtD's also right about the photos; if you can only send one, make it color and make it GOOD quality. A professional portrait photographer — preferably who has some experience in this kind of thing — is worth every dime. Stay away from dark, moody shots, even if she plays dark, moody music. They don't reproduce well and they'll just wind up in the trash. Papers want something they can use for a display shot (wider shot, with instruments, etc.) or that they can pull a mug shot (just head and shoulders) out of.
Don't tag agent, booking info, web sites, etc. on the end. Put them in the letterhead, preferably in an eye-catching but not gaudy typeface and color.
And, above all, know who to sent it to. The best press kit in the world won't help a singer if it winds up in the sports editor's hands. Go to the library and get the LATEST edition of Editor and Publisher and look up the entertainment editors.
Good luck,
david