I am a beginner, and the list reflects that. This is the method.
In the field. Photograph first, identify afterwards. A poor photograph of an unfamiliar bird is worth more than none, because the identification can be resolved later from the image.
At the desk. Identification is based on field marks such as structure, bill shape, plumage pattern, habitat and season, checked against reference works. Identification apps are used as one input among several, and their suggestions are always cross-checked against the field marks before anything is accepted. Where the two disagree, the field marks decide.
Groups treated with caution. Juvenile large gulls, dowitchers, small Calidris sandpipers, Empidonax flycatchers and Tachycineta swallows. These are recorded only where a photograph shows a feature that settles the question.
Threshold for listing. A confident wrong identification is worse than none. Where a photograph cannot carry the identification, the bird is not listed.