How to layout diagonal floor terracotta tile? ...
Answers: Find the center line surrounded by the room for both directions. Snap a chalk line for those which will splotch the center of your room.
Now, start from the center and dry fit your tile with the corners running on the center dash (don't forget to use your spacers). Dry fit out to the walls to see where the closing tiles will fall. The object you want to do this is to check to see if you want to off-set your center line a small amount to avoid have to install a very small run of tile at the circumference of the room. If you are happy next to the layout, continue dry fitting.
For the DIYer, the locked thing to do is to dry fit the entire room. Once you hold that, you can start laying the tile starting at the center smudge on the far wall and work your way out to the other walls and later start working your way across the room.
I other snap 2 chalk lines diagonally. Then lay tile from the inside out.