To find the Perseus constellation, first search for Cassiopeia, the bright constellation shaped like a "W" or "M" depending on time of night. It's directly across the North Star, Polaris, from the Big Dipper in the Ursa Major constellation. Perseus is always located just beyond Cassiopeia.
Before attempting to spot the Perseus constellation, look at a celestial map or star chart to remember its shape and find out if it is viewable during a particular season or from a certain location. Ideal viewing conditions are in mid to late autumn and early winter. Cassiopeia is much brighter than Perseus and has a much simpler design, making it easier to spot. The bent "Y" shape of Perseus is slightly more spread out, and some of the constellation is likely to be blocked by the horizon early and late in its viewing cycle.