How do you know which way round a 6-pin SOT23 goes?

There are two ways to identify pin 1 on a SOT23-6. One is a dot next to pin 1 on the top of the package. Most often it's not printed with the marking, but molded as a small pit in the plastic of the package, often no more than 2/10s of a millimeter in depth. A second method is a chamfer over the length of the package on the side of pin 1. From the drawing in the datasheet both the LT1933 and the LM2734Y should have the pit/dot.

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FAEs often have warned me never to refer to the marking printed to determine which is pin 1.

Sometimes they have a line along one edge.