Start with the named ones
Chickadee (says its name), Northern Cardinal ("birdie-birdie-birdie"), White-throated Sparrow ("Oh-sweet-Canada"), Mourning Dove (the mournful coo), and Blue Jay (the harsh "jay!"). Five voices cover most of what a yard says — and the ear, once calibrated, starts sorting everything else by contrast.
The repetition trick
Songs repeat: the cardinal repeats his phrase, the titmouse repeats "peter," the mockingbird repeats everything twice. Counting repetitions is an ID tool — and once you hear the structure, songs stop being a blur and become sentences.
Dawn chorus and the calendar
Fifteen minutes before sunrise is when every voice sings at once — the dawn chorus is the day's bird census. Season shifts it: spring adds migrants (warblers passing through), summer holds residents, fall quiets to jays and crows. The same yard is a different concert each month.