When writing an artist bio, all you’re doing is letting people know who you are, and what you do. Those two things should be in your head at all times when writing one of these things. I don’t want a long convoluted story about how at the age of 11 you picked up a guitar, or how your parents used to play Motown 45s in the house all the time - I want to know who you are, and what you do.
Keep it short, keep it snappy, and try to avoid release details. I can’t emphasize that enough, as all too often bands get carried away with bios and start talking about albums that are “coming out soon” in 2011 and forget to update it 3 years later, so instead of the bio acting as a little introduction to who you are and what you do, it becomes a kind of weird time capsule. It also shows you’re not bothered enough to update it over 3 years, so stay away from it.
Who are you, and what do you do: I don’t want to read 15 paragraphs of life history, or philosophical quotes about how much music itself means to you. It doesn’t mean anything, and it doesn’t help me figure out who you are and what you do.
Acknowledge the silliness of having to write them if you have to, and break the wall between you and the audience. It’s ok. It’s fine. Try to keep it in the first person as much as possible too, as doing stuff in the third person makes things tricky and insincere.
A few choice namedrops are OK, like if Steve Lamacq loves you, then sure, feel free to bob that in, but don’t give me a massive list of every publication that’s ever mentioned you. It’s boring, and if you’ve really been that well received, I’ll pick up on it anyway. It’ll speak for itself, in other words.
To sum up: keep it short and sweet, avoid release details, and don’t include your musical CV.