-check out Steve Large "The Owl Man" largesdotca
-best time is Sept/Oct
-arrange to participate in a night of banding at Rocky Point Bird Observatory
save their site as a favourite so you know when the owls are moving through
-if you are out and hear a tree 'a-twitter' with Kinglets, Chickadees & Steller's Jays, take a really close look. you probably have a Northern Saw-whet.
-check with your local birding group for possible locations
-the rest is luck. good luck!