Usually, distances between stars in the night sky are quoted in angles. But what angle are we really talking about? Suppose observer 'O' says that star 'B' is 'x' degrees away from star 'A'. This means that the angle BOA is equal to 'x' degrees. Since the stars are too far away, observer 'O' can be assumed to be at the center of the Earth.
Although the clock system is a very helpful tool to point out stars, it can only give the general direction of the star relative to the reference star. To exactly mention which star you are talking about, you need to somehow convey the angular distance approximately. Here, we will try to do exactly that.
Fully stretch you hand horizontally in front of your eyes. Now, close your fist. The angle between the two ends of your fist is approximately 10 degrees. This means that if you can see one star at one end of your fist and another at the other end, they are 10 degrees apart. Now, stick out your thumb (as in thumbs up). The angle between the tip of your thumb and the far end of your fist is approximately 15 degrees. Now, stretch your thumb and little finger as far apart as you can. The angle between the tip of your thumb and the tip of your little finger is roughly 20 degrees.
Note: Stretch your hand fully while doing these measurements.
Using these two tools, you can easily point out any star once you have a reference star. However, it is a good practice to choose a reference star as near as possible to the star you're attempting to point out .