As a dance teacher, your bio is basically a narrative version of your resumé. On a website it's your best public-facing advertisement, and it's often the first impression that parents, students and everyone else has of you. That said, writing a good bio isn't easy! Some people find that they aren't comfortable bragging about their background, while others may leave out information that readers would definitely want to know. There are numerous challenges with getting the balance just right.
This doesn't mean you are doomed to having a basic play-by-play-type bio that reads like a laundry list of basic skills and past teachers. There are a variety of different ways you can improve this tool and give an informative summary of your experience that will help people learn more about who you are—and what your philosophy is as an instructor. Here are some things that you can do to make improvements.
Have someone else write it. Get in touch with a local freelance writer, or work with someone you know who has good writing skills. A person on the outside can often lift out the most important highlights in your background and make them sound as impressive as they should in your bio. It's easy to downplay your own skills in the name of humility, but when someone else is at the keyboard, you'll be more likely to sound your best on the screen—or on paper.
Write both a short and long bio. A short bio is something that you can use for just about any purpose, and it should hit your very biggest accomplishments and/or best associations to give readers a broad idea of who you are and what your background is like. Go for 200 words (about a paragraph) or so and keep it simple. A long bio is something you should consider including on your website (or the studios where you teach), and this should really delve into all of the experiences you've had that make you unique as an instructor. It's good to have both at your disposal.
Know what to include. If you have studied under someone with a known "name" in the industry, be sure to include that (and hyperlink it on the web if you can), as well as any major school associations you may have. Naturally your years of experience, teaching jobs and any awards you've won belong in a bio, but think beyond that and look to any standout experiences you've had, too. Also try to include something about your teaching philosophy to give people a sense of who you are in the classroom. A current photograph is optional, but definitely preferable.
Keep things updated! It's easy to let a bio slide on past accomplishments or associations, but updating it periodically is something you should definitely prioritize. Be sure to add any new accolades, certifications or accomplishments as they happen, or, at the very least, once a year.