Learn the criteria of the bio and whom you're writing for. For example, is it for a casual fan reading a music magazine or is it for a trade convention? If it's the latter, then a laundry list of musicians the producer has worked with may simply be an aside, as the focus should be on his innovative recording techniques, if applicable. However, if it's a producer who is looking to promote himself and drum up business, then a little name dropping might be in order.
Collect the information about the producer. If the resume isn't extensive, include the minutiae that both makes her look good and is relevant to the bio. For instance, say she was a well-known studio engineer before she took the helm as producer. Mention how she always found a way to get the artist the exact sound he wanted, if that's the case. On the other hand, if the producer has been around awhile, focus on the highlights of her career and avoid a tedious, blow-by-blow account of the resume.
Tie in biographical information that relates only to the music. Granted, you should include personal information, but try to keep it pertinent to his music career. You don't want to bog down what you write with irrelevant information about, say, his third-grade hobbies. For example, if the producer played in a band before landing his current production job, mention it only if he had a reputation for being more interested in the technical aspects of the studio back then.
Condense the facts to fit the bio on one page, as this is generally an adequate length. Remember, you're not writing a book on her; you're simply summing up her career highlights in such a way that they can be read in a few minutes. Chronological order is important, but feel free to begin with something creative that encapsulates what drives the producer and makes her tick. Then, go on to list the accomplishments.