i would say to first consider what type of item you would like to
polish/ finish, and what type of finish you desire.
is it flat?
is it highly detailed, with recesses, or raised areas?
does it have crisp edges?
does it have rounded edges?
what type of finish do you want?
different tools and techniques produce different results.
select the tool(s) that will give you the result you want.
also, when you are finishing/ polishing, you are refining the
surface by removing scratches and imperfections, and replacing them
with progressively finer scratches, until you reach the desired
finish, by using a progressively finer tools (ie: files, burs,
sandpaper, abrasive wheels and points, rubber wheels and points,
buffs and polishing compounds, tumbling media, steel burnishing shot
or pins, just to name a few, which all come in different cuts,
grits, and profile shapes)
the finish produces can be rough, matte, satin, shiny, mirror
finish, and everything in between.
when i was just starting out i got jewelry tool catalogs and read
them coverto cover to get familiar with what tools were available,
and found that very helpful, and fun too!