I got this in an e-mail from a friend...
Don't know if it's effective....but i guess it's worth a shot.
10 Ways to guard against Ghost in Hotel Rooms1. Knock on door or press door bell before entering, meaning to ask
for permission to stay there.
2. When entering hotel room for 1st time, enter sideways so as to
allow the 'dirty thing' to leave the room.
3. Leave a pair of slippers (each facing opposite directions) at
door entrance. 'Dirty thing' coming in will follow the slipper and
go out.
4. Place a glass of water and a pinch of salt at head of bed.
5. Flush toilet bowl before using. (This one damn "duh"..

)
6. Do not close the bible if it has been left open.
7. Avoid wearing black & red clothings. Wear yellow clothings.
8. Before sleeping, close toilet door & also switch off toilet
lights.
9. Don't sleep facing big mirror.
10. Before sleeping, do not leave slippers together but each facing
opposite direction to each other or in a messy way.
Out of all, i believe in No. 4.
Salt has extremely powerfull cleansing effects.