How to unfollow people who are not following me in Twitter?

[Kasun!]

I already following more-than 250 people in Twitter and also i have followers 100, and i have 128 tweets.

1).So how do i detect who are not follow me if i following them? And how do i remove them in my account.
2).And also how do i check people who are following me but I'm not following them?

[Penny]

to remove people go on their profile and at the top right corner it says unfollow so click that and theyll be removed. You cannot deleted people who are following you though

[Tech]

You don't want do it manually , its already tools there to do this kind of task the tools are

1.socialoomph
2.friend or follow
3.your tweet karma.

so by this tools you can do the task well