I don't understand where to use so called..
sometime it feels completely unnecessary to use so called...
Does that mean something?
Does it express some kind of feeling?
These so-called actors are just waiters who have an interest in amateur dramatics = These people who refer to themselves (or are sometimes referred to as actors) are simply waiters who want to be actors.
The so-called superbugs have killed thousands of people in the last few years = The bugs which are commonly known as superbugs have killed thousands of people in the last few years.
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.