stop believing in them.

Know the facts that outside of Hollywood there has been no documentation recorded that showed where a ghost has ever harmed anyone. The only harm in this manner has been people harming themselves through fear.

Just remind yourself that your emotions work for you, and you don't work for your emotions.

remind them you will be there haunting them someday

Embrace them. I embraced all my fears, and no longer fear them. I slowly overcame my fear of heights and am going sky diving hopefully this year or next with my buddy who's already gone once.

Be scarier than the ghosts.

Remeber they're not real?

Consider the fact they don't exist

If you believe they exist, tell yourself that most ghosts, in popular belief are merely lonely, and sometimes stuck in Limbo and even completely oblivious to your presence. There's a lot of different explanations as to why they might be here and what they need to do, but actually, not many of these explanations suggest any kind of ill intent from them. There are some, apparently, who want to tell you something, sometimes it could just be a dead relative, or even a dead pet, wanting to say goodbye. Sometimes they just have an important message and won't give up until you hear it. Other times, they might need help from someone to complete an unfinished task or whatever. Although there could be poltergeists (Violent ghosts.) or ghosts that do wish to bring harm, mostly I think that is the stuff of the movies. Some may just be really angry, and unless you're willing to comply and satisfy them, because if ghosts exist in popular fashion then there's ALWAYS something to end their reign and send them to their proper place, there's not much to be done about it. I can't give any advice because I've never seen any ghosts nor do I even believe in them in such fashion, but like many things on Earth we know nothing of, I think you have to read between the lines of occurrence, no matter how much your instinct tells you to flee. We don't know much about them so it's natural to be afraid. :/

if you believe there are ghosts out there to hurt you then why can't you believe that there is an ulimate protector watching over us, protecting us. So whenever you come across a ghost or something bullshit like that sing them their favorite song, which is any of your religious song or something like that. Trust me, they hate these stuffs.