How do you use Twitter?

I've seen many sites ask for my Twitter info (Hashnode included) and many developers share their Twitter account. Unfortunately, I have yet to find out how to use Twitter efficiently; that's why my Twitter account has been quite empty and unused.

How do you lot use your Twitter account? Do you just follow people? Who do you follow? Do you write stuff? What do you write? Do you try to get a big network? Or do you cherry-pick useful contacts? Why do you do so? What kind of advantages do you see in your daily life?