Up and up

Hi guys,
I haven't had a chance to take many pictures lately so am playing with some old ones (though the next one I take of this will be with it lit up to make it a bit more interesting!)
This one I have straightened to what I think looks right but would like to know: is there is a general rule about which line is best to make vertical with these stuctures? I do struggle with this a bit.
Thanks for looking,
Elena

I haven't had a chance to take many pictures lately so am playing with some old ones (though the next one I take of this will be with it lit up to make it a bit more interesting!)
This one I have straightened to what I think looks right but would like to know: is there is a general rule about which line is best to make vertical with these stuctures? I do struggle with this a bit.
Thanks for looking,
Elena
