One of the most difficult skills to learn in drawing is how to make your drawings look realistic. Why is it that some people are able to translate what they see onto the paper so well? If they draw objects or people right in front of them, the angles of the edges turn out right! How do they do it? -They practice sighting!
Here is a simple way to think of it: Imagine the hands of a clock, where they point shows the time. If we are looking at a clock and the time is 11 o’clock then the clock hand is almost fully vertical as it points to the number 11.
If we are drawing something, and wish to sight the angle of one of its edges- simply hold up your pencil (see above) and close one eye as you align it along the edge of the thing you are sighting. I put the edge of my pencil right next to the edge of the vase, then I can see what angle to draw on my paper. My pencil below is at 11 o’clock.
Here, my pencil above is at 10 o’clock. So if i want to find the edge of the very top of the tea kettle, and see where it is in relation to the blue vase, or in relation to the top of the gold vase- I simply place my pen or pencil along the top edge of the handle and I can see that my pencil runs right into the top of the blue vase, and that it is below the bulge in the gold vase.