opps mistake its beans in the first new rows being added and another plot of corn will be added later than that.

Put you tallest plants an the north side so that they don't shade the shorter ones.

I say put the tallest (tomatoes and cucumbers) in the middle. The shorter heat and sun loving plants (zuchinni and squash) go south/west. The plants that like a little shade and cooler afternoons go to the north/east (lettuce, onions, oregeno).

I lay my beds out with paper and pencil first noting any trees, bushes, structures and north south east west. While I don't usually follow it strictly I find it helps alot.