You have to use a third party app to do this. They will require that you submit your log in details so they should be used with caution.
Nobody really has an auto follow back but some famous accounts will follow a lot of people back. For example, Barack Obama follows a lot of people back. (Although, it's not actually him doing the following)
Just click on the follow button to follow back that twitter user.
follow me on twitter @kevindarnell i follow back
They can either follow you back or not . they can direct message you or mention you in a tweet .
Twitter allow you to follow starting 1800 individuals individually. After the 1800 follows twitter monitors your followers. If you are not getting followers in return Twitter does not allow you to follow any further profile, as long as you get the follow back.
Go to Google and search for FT Video's Twitter page. Once you're there log in if you haven't already or register an account. After that you go back to their Twitter and click Follow.
follow me on twitter @kevindarnell i follow back
Tweetoid.
There are many fraud accounts in Twitter but to get the real person follow you needs effort. Follow them, engage with them and they will probably follow you back... I don't think FREE followers are quality followers.
Follow a bunch of people that shares the same interests with you, make friends with them then ask for a follow back.
follow me on twitter @kevindarnell i follow back #teamfollowback
You make a twitter account and then follow him