Follow back it works

Follow everyone who follows you-

It might seem
counterintuitive to do this
when you're focused on
gaining followers, but it's a
good practice because:
People who notice that you
didn't follow them back
might unfollow you.
When you follow back,
some people might
respond to you publicly,
which will give you some
added exposure to their
followers.
If you're worried that you
won't be able to keep up
with that many people,
you're right. Once you're
following over 100 people,
it'll be pretty much
impossible to read all their
updates. You'll become
more selective in who/what
you read.