Traditional feng shui relies upon the compass to give accurate readings. However, critics point out that the compass degrees are often inaccurate as fluctuations caused by solar winds have the ability to greatly disturb the electromagnetic field of the earth. Determining a property or site location based upon Magnetic North will result in inaccuracies because true magnetic north fluctuates.
For the first position: feet facing the closet door should be ok, if it’s not the door of a walking closet. As for the edge of the closet, can you place the edge close to the wall? It’ll help mitigate its effect. Having the window beside you is acceptable if it’s not right next to your head. However, there’s still some health consequences from the outside wind that you should watch out for.
It's hard to rest with too much active energy around you. You have to be aware, for example, of what electricity is running behind your bed. Try to minimize it with a battery-operated alarm clock instead of an electric one. Turn off your phone at night and keep it out of the room. No laptop or computer near the bed. An hour before you go to sleep, stop looking at it.
Check your flow of chi. You can check your flow of chi by closing your eyes and imagine chi as a deluge of water that comes in the front door. Are there any spots of the house that will never get wet because things are blocking the way? Does energy get blocked before reaching your bedroom? Do you have good energy (sheng chi) or bad energy (si and sha chi) in your home?
The oldest examples of instruments used for feng shui are liuren astrolabes, also known as shi. These consist of a lacquered, two-sided board with astronomical sightlines. The earliest examples of liuren astrolabes have been unearthed from tombs that date between 278 BC and 209 BC. Along with divination for Da Liu Ren the boards were commonly used to chart the motion of Taiyi through the nine palaces. The markings on a liuren/shi and the first magnetic compasses are virtually identical.