always have a bio, but keep it to the point, don't share your medical record, life story, family life, social life or that you just started, really need the money or stuff like that. tell people what you make. google finds this as well and gets people to your page. don't link out - like saying - please friend me on facebook. not only do they leave and not come back, but it looks lame (i've seen this so many times)
don't call a gallery "playing around" just call it "illustrations" or something, it sounds more professional.
---Mike Savad