Personally, I don't think that twitter is the best measure. Given the amount of noise and the whole follow back culture, you might just end up getting the 1/10 person who ends up following everyone.

I think if you are going to use twitter, have something interesting to say about the area where your startup is based in - that will attract initial early adopters and those who are passionate about the space.

Also, I do feel if you have some JS, CSS knowledge, go out and actually build a landing page - see if people actually sign up to what the product will be (or could be) - that's a much better way to gain traction and email addresses for those who could end up being your early adopters.