One thing I have learned when trying to take window shots is not to stress out about what seat you get. In the end, 95-96% of them will turn out poorly, with the dirty windows and specks of frost that form on the window anyway. Just pick a window seat, if its a filthy window, move really quick, take some shots and enjoy your flight, don't overstress about where you sit.
One other thing is that sometimes sitting over the wing can provide nice angles. Especially if the plane has winglets, so you should be able to get some good shots regardless.