1. The movement signature. Open the back safely (see 'How to Open a Pocket Watch'). Note the name, place, serial number, jewel count and any grade or calibre markings on the plate. The movement is the most reliable evidence of who made the watch.
2. The winding and setting. Key-wind generally points to earlier work, before stem winding became common in the later nineteenth century. Stem-wind with lever setting points to American railway or better-grade watches. Stem-wind with pendant setting is the most common later arrangement.
3. The case. Look inside the back for marks: the case maker, the metal ('14K', '0.800', 'gold filled', 'coin silver'), patent dates and the case's own serial number. American cases were usually made separately from the movement. A good match between the case and the movement's era supports originality.
4. Hallmarks. British silver and gold cases carry assay office, standard, date-letter and sponsor's marks, and these can date the case to a specific year. Swiss cases may carry control marks and standard marks. See the hallmarks guide and markings section on this site.
5. The dial and hands. Note the dial material (enamel, silvered or metal), the numeral style, any sub-seconds dial, and whether the dial name matches the movement. Refinished dials and replacement hands are common.
6. Put it together. Check the movement serial against the maker's table, then check that the case, hallmarks, dial and style all fit the same period. Where they conflict, record the conflict: the watch may have been recased or assembled from parts.
The Identification Centre and the photo-assisted identification tool on this site can suggest records to compare against. They give clues with confidence levels, not definitive identifications. For valuation or authentication, consult a qualified specialist.