What's the best way to snap lines.
Use a chalk box!
OK OK OK, sorry 'bout that!
You must determine what you want to see. If "balance" is of the utmost importance to you then that's easy. Evenly divide the area and go for it.
If you want more design appeal and balance doesn't make that much difference then you need to determine the best placement of the layout for visual impact. Not all tiles have to balance in that case.
For example maybe the kitchen is more important visually than a laundry room so the layout should favor the kitchen focal points and take what you get in the laundry room if you want the tile to flow continuously throughout the area.
Take a look and see what you want to do. Then layout your floor accordingly.