1.) Do not allow yourself to become as negative as them.
The saying "Misery loves company" is complete truth. A narcissist is going to try to do everything in their power to try and make you become as judgemental and hateful as they are. They are convinced that they are on top and all else is below them, including you.
2.) Do not let them bring down your self-esteem.
For me, this was the most difficult one. Narcissists are known for needing to bring other people down in order to make themselves feel better about how shitty of a human being they really are. If you get too close to a narcissist it will not be long before you find yourself struggling to look in the mirror at yourself.
3.) Do not let them isolate you.
A narcissist needs to feel like they are the center of your world. They need to make sure that there is no one else in your life who could potentially be above them in your eyes. So as a result, you may find yourself feeling so incredibly alone while they have a number of friends.
4.) Do not let them play mind games with you.
Narcissists love to make you seem like the crazy and unstable one. To do this they will say one thing but then there next action completely contradicts what they said. You will be left wondering if your sanity is still intact. Trust me.