If you think it's difficult identifying a Swiss made wristwatch from the 1960s, just try dating pocket watches. We have had some real interesting ones here since Ernie changed the name of our forum.
So I'm going to give some brief tips on how you can do it. Of course, JohnF and I will be around to help you but for your interest here goes from easy to harder ID work.
(1) If you have an American made watch built after 1860 or so, or a famous brand like Omega, well..Bob's your uncle. The serial numbers records for the watch movements are available online or in a common book like Shugart's price guide. You can nail these right down to the year of manufacture. Case serial numbers are useless, by the way. You need the number off the movement.
(2) If you have a silver or gold cased English watch, the hallmarks can often give you a clue as to the year of manufacture.
(3) If you have a verge movement, chances are your watch is older than 1850.
(4) If you have a double cased watch with inner and outer case, your watch likely dates to before 1830.
(5) If you have an English watch with a chain drive and English lever movement, your watch was likely made between 1850 and 1910.
(6) If the dial of your watch is ceramic, the watch was probably made before 1920.
(7) If you have a cylinder escapement in your watch , it's likely not English but it could have been made anywhere from 1740 to 1940. You'll obviously need more clues.
(8) If you have a Swiss lever (straight line) escapement your watch was likely made after 1840 but they're still making them so....