Flooring Tile - Where to start tiles

I have a kitchen and small eat-in area of about 18' x 10'. The base cabinets also extend in an L out in the kitchen area. Also there is a Pantry room also extending a few feet in the eat-in area so this isn't straight forward measure. I need to figure out where to start the tiles? Do i measure the lenghth of the room and the width to find the center? I have two doorways and i didn't want the tiles to look off center there. I am at a loss as how to measure and lay the chalk lines out.

Find the area that you see the most, square it up and then set the tiles dry and ajust them till it works, could take awhile, try and get cuts to be 1/2 a tile or more, don't worry if there are small cuts somewhere, might be unavoidable.:)