The first and most important step in the fight against everyday prejudices is to recognise them, and to acknowledge that we are all affected by them. Everyone has definite ideas about certain groups of people that never apply to all members of that group. If you are, and remain, aware of this fact, you have already taken the biggest step.
The second step is to try to make sure that your own prejudices do not determine your behaviour. Prejudice should never lead to exclusion or discrimination against others. Also, make sure that you do not spread your own prejudices.
Step three: react! If someone around you hurts other people, insults entire groups, or uses prejudice to define them, react. Oppose them! React in your own circle of friends and acquaintances, respond on social media.
How do you do that? You can ask people to tone it down. You can discuss the issue or make yourself heard in another way. You can let people know that you are not okay with offensive or insulting prejudices - whether they affect others or yourself.