I asked a similar question and had a wonderful response from a fellow hub writer who said to be sure always offer something to your twitter friends. It doesn't always have to be about your focus either. People in the same fields tend to have similar interests. For example, language interpreters tend to be interested in gardening and writing! Go figure. (That's how the Strong Campbell Interest tests for finding a career were normed - on similarities of hobbies and interests in people in a certain field of endeavor).
I found that I get followers on twitter without trying related to each name I use. I had chosen leftpawedpuppy as a Twitter name because It's actually part of my children's ebook's name, BUT people cue into the name and follow you because of it. With that account, I get all kinds of dog grooming, pet stores, etc. following me out of the blue!
When I figured out the relationship to the Twitter name, I opened another account when I wanted to promote my Academy Award Solitaire game under "billiehollywood". That gave me "permission" or a logical reason to post links OCCASIONALLY to my game and then to comment on other matters related to the Academy Awards. You can also search for "career moms" as you know in twitter if you want to get more of that audience or maybe "Parent tips" or "hints for moms" on twitter and follow those people, always remembering to be generous in your offerings and "not overly commercial" as my fellow hub writer suggested.
I tweet the great hub articles here that are related to my twitter account. For example, if Dr.Mark, the veternarian posts an article about dogs, I tweet it on my leftpawedpuppy account. Then later that day, I might tweet the link to my book. If we all did this for each other, we'd have lots of synergy (if that's the correct use of the term).
If you search for "twitter tips" here on hubpages, there are some Great hubs on that topic. PS, when I went to your profile and tried to follow you on Twitter, the link didn't work, so I can't find your twitter name. I can tweet this question from here, but don't know by what name to follow you.