Row 31 is excellent if you want ample legroom and the flight is crowded. If you can't have the adjacent seat blocked, best to be in a seat which gives you unlimited legroom.

These seats also have in-chair personal-TV on the same type found in Business class. If you don't plan to sleep, it's the best seat.

If the seatmap looks pretty open, you should look for row 32-33, center section. There's more chances of an unoccupied row for you to stretch out in the back half of the plane. The front coach section is usually crowded because of the power ports. 32-33 still has power ports but helps to maximize your chance of grabbing a full empty section for sleep.

If it's a medium-crowded flight, go for the front coach section (any row before 30) and grab one of the 2-seat sections.