If you have an odd sized room you'll want to find the center of your focal point which may not be the exact center of the room.
I.E. walking into the bathroom you want the largest longest area that you see of the floor to be your focal point. Offsets for toilets, vanities extra will follow.
Set your focal point center line from the wall and dry lay some tiles to see how things will look. Shift your center line as needed to get the look you want and minimize cutting or odd sized tiles.
Spend as much time as needed on your dry layout before actually setting the tiles. Its the key to getting the look you want.