If on Acela (business, not first), and you want a full window view (not blocked by the wall between windows), pick an even row in the northbound trains, and an odd row in the southbound trains. I finally figured this out when going to NYP last month.

This does *not* apply to the four-seater table rows, as those rows do not change their orientation when the remaining seats are flipped at the end of the run.

Conversely, if you don't want the distraction (or whatever) of a window view and you actually like having a largely blocked view, pick an odd row in the northbound trains, and an even row in the south bound trains.