I don't SEE ghosts, themselves, but here's something you might want to try:
Use a Oija board. Ask who's there. Ask how many are there. You can't be joking, this is very serious. Put all the lights out. Keep someone near in case you might get possesed, hurt ect. by a spirit. Ask very MEANINGFUL QUESTIONS! Nothing like "Can you turn my IPod off?" or "Move the table into the corner!". That will get them mad enough to want to KILL you. I used one once. A chair flew FROM DOWNSTAIRS to my freind's room UPSTAIRS!