My main question is how does one determine which side of the doorpost a Mezuza should go on? I believe (though I cannot quote a source) that it is supposed to go on the right side of the door, with the right side being determined by where you enter the room from. However if you have two separate entrances to the home (like a front door and side door) how do you determine where the entry of the room truly is?
Also how high up on the doorpost should the Mezuza be?