Lazy Way to A Big Following
6. Get yourself a TwitterBot, set it up to pick the Trending Tweets and have it automatically follow other Bots, a Bot will almost always Follow you back as it uses your Tweets like Trill.
There are about 27 million active Bots as of 2016 and the number is growing exponentially. (about 10 million in 2014)
How many Followers do you want ?