At a recent demonstration of quick sketching techniques I was asked how I handle the challenges of accurately drawing such things as complex architecture. My reply was that I do not concern myself much with being accurate. I freely change the relative sizes and positions of items in the sketch, to simplify a scene or create a focal point. I usually sacrifice accuracy for speed.
In this recent sketch at a market day I included a tall tower and really messed up the geometry at the top. Not a problem, as the center of attention is much lower.