A breezy day pm the rooftops.
I used the 'fill tool' for this one;
Easy steps are to carefully follow the video. I added the grey fill in the shape of anime/manga hair, adding on I got the roof shape out of it, added the chimeneys and created the other rooftop off of the first; adding on the chimeneys one again, I used the grey and added shadows and light from the grey sky.