If the moon is in the sky, it can also diminish the number of meteors you observe. However, this would mean you would stare at the entire sky for an hour only to be rewarded with a single meteor every 10 minutes. The chances of looking in just the time and place are not good. Well, as explained above meteors are caused by dust that the Earth runs into in its orbit about the Sun. Thus, during a meteor shower the Earth is plowing through a greater number of dust particles than on a non-shower evening.
Comets are something like dirty snowballs that populate the very outer parts of the solar system.
However, sometimes they fall in towards the sun and orbit in large elliptical paths. So comets leave tiny particles in their wake, and should the Earth pass through one of these streams of dust in its orbit around the Sun, many meteors will be seen. Every year the Earth passes through a stream on the night of August 11th which is responsible for the Perseids meteor shower. It takes 365 days to go through 360 degrees so that each night at the same time the Earth faces about one degree to the East further than the previous night. The meteors are actually entering the atmosphere in parallel trajectories.