If you're on Twitter, it's really important to fill in the Bio section. You can use up to 160 characters so make good use of them.
Your bio should include words that will help people find you if they're searching on Twitter for companies or people that provide the services and products you provide. For example, if you're an accountant, make sure you include accountancy words and your specialisms in your bio, eg "Accountant, Tax Specialiast," etc. It's ok to say you're a fun-loving mother of 2, but if you're using Twitter for business, get some key business terms in there as well, otherwise no-one is going to find you. Mine is: "Marketing agency co-owner, website design & build, SEO, social media, email marketing, consultancy. Also co-owner of webmakercms.com & amateur pianist." There's quite a lot you can get in there so make the most of it.
Another reason to make sure you fill in your bio is to help them decide whether to follow you or not. If they see a tweet they like or see that you are following them, they're going to look at your profile to see what you're about. If you haven't got a bio, how will people decide if they want to follow you?
And finally - you absolutely MUST have a photo of yourself or a logo of your business. If you don't upload a photo, Twitter will just substitute the anonymous "egg" image, so people will think at worst that you're trying to hide, or best that you're just incompetent. That is not going to make them want to follow you. So get a nice head and shoulders shot of yourself and upload that, so people can see who you are. This also helps when you're at networking events as people can recognise you if they've been tweeting with you.