Owls don't have very big hunting ranges so if you see one on a light pole, watch it for awhile and see if it flies to a particular tree. With great horned owls, the pairs and family groups call to each other, usually at dusk and dawn so you can follow the hooting.
Barn owls tend to only come out at full dark and also tend to sleep in the darkest parts of trees or in holes in the ground and so are much harder to spot. One year we had a barn owl nest in the neighborhood and the noises they make when calling to each other are amazing, otherworldly.
Spotting screech owls requires hanging out at dusk through full dark and listening for their calls. They have very small hunting territories so if you hear one, you can focus on that area during the day.
Most of the owls prefer clear flight paths so watch for them in fields and along open roads, trails, and creeks.