given the Twitter api call limitations, how to get a complete list of all the users not following you back? There are so many methods (friendship lookups, followers and following lists) that I don't know how to do this in the most efficient way.
Thanks.
You can use this to find your followers : https://api.twitter.com/1.1/followers/ids.json?screen_name=your_screen_name
You can use this to find your following : https://api.twitter.com/1.1/friends/ids.json?screen_name=your_screen_name
And finally compare both Json data and the one that you are following but not in followers list is your not following back list of data.
Not following back = following - followers. You will need to use php or any language that you are comfortable with or making your application with to do the math for you.