If you follow this simple technique you can find the all 20 Glyphs so easily. During
gameplay, when you come in a new place where traditional architecture like building,
palace, bridge etc are situated, you can see their database by pressing "Tab" button. 
And the technique is right in here. If you see an "Eye"-like sign above the database, 
then it means that a Glyph is hidden in that palace/building/place. Now search the 
area and you can find the Glyph easily. The work will be easy if you keep a sharp eye
in every new database. Besides you can also see how many Glyphs & secret locations are
in a city to find out. To do this, pause the game and enter the "Locations" subfolder 
under the "Database" folder from the menu. There you can see every database in each 
city and you can also identify the Glyphs locations in each city by seeing the 
"Eye"-sign icon above a database. So you can now easily find all the Glyphs throughout
the game.