Most pocket watches that you encounter will have a
name of the maker on the face of the watch.  In some
instances, the name is not a recognizable maker name
see Fig. 1).  This is an example of a private label
watch with the jeweler's name "Frank E. Davis".  When
we open the back of the watch up, it indicates that it is
actually a Hamilton watch (
Fig. 2), but the jeweler
cased at the shop, and had a number of dials made
with the shop name.  As chance would have it, I
happened upon a reference to Frank E. Davis of
Northampton in a "Jewelers' Circular" dated Jan. 11th,
1899.  You can view the
excerpt here.
Contact me or call 530-520-1478
 A serial number (found on the movement, not on the
see Fig. 3) is also a helpful piece of information,
as this can be looked up on any number of databases
online to ascertain the date of manufacture, and
grade of the watch.

As most watches were cased after the movement left
the factory (or if the watch is re-cased at anytime
during it’s lifetime), information on the case is not very
helpful for identification.

If you cannot locate any written information on the
face or the movement, it is often a blank movement
manufactured overseas, and finished out by a jeweler
to whatever specifications were desired.   These are
called an “ebauche” movement, and can range from
very low to fine quality.

NAWCC Chapter 190 has a very informative page on
opening watch cases, as well as images at :
Identifying Your Antique Watch
fig. 1
fig. 2
fig. 3