Most of the time a publisher will want you to write your bio in the third person. It is tempting to get cute and write "Alisa often refers to herself in the third person," but it has been done. In fact, the good thing about having to write about yourself as a she or a he is that it gives you some distance. Use the distance. Stay far away from too cute, too earnest, too anything. What's that phrase you always hear? Oh yeah, be yourself.
"Yourself" should be crystalized in about 3-5 sentences or about 50-100 words. These sentences should say why you are you and not someone else, and what is it about you that is distinctive. What do you do? Where? What else is different or interesting about you or makes you particularly qualified? Does your degree make it better or worse? Keep it simple, flavor it slightly, if you like.
Some strange examples I've seen are huge paragraphs listing every website, every publication, and a person's business venture in detail. The long lists of publications are not very interesting. Pick a handful and say "among others" or something similar. In a magazine I once read, a bio said the writer had been published in over one hundred other magazines; I couldn't help feeling sorry for her—wasn't it time to move on?
If Dr. Seuss were here (1904-1991), he might write something like this (no, maybe not, his would probably rhyme). But anyway, I've written up a simple possibility, with info gleaned from this article.
Theodor Geisel, known as Dr. Seuss, is a writer and artist, best known as the author of numerous children's books written in rhyme, including One Fish Two Fish Red Fish Blue Fish and Green Eggs and Ham. He has an extensive hat collection and often puts on skits with knives and spoons. He lives in La Jolla, California.What do we learn? He writes under a pen name. His work rhymes. He is also an artist. He has an extensive publishing background, but he's modest about it. He is playful. He lives in California. I mentioned his hat collection, in this case, because it seems to inform his work and the skits because they give him a human dimension. 58 words. It doesn't have to look like this, but this is one way to do it.
Okay, so you're not Dr. Seuss. All I can say is be confident. Your bio is there to put you and your work in context. You are worthy. Your work is worthy. It will shine on its own.