Hi Will,
a quick way to see if the label engine is trying to label the features but they're not fitting is to click the unplaced labels button. this is on the Labeling toolbar
Customize > Toolbars > Labeling
it's the tag icon with the red x on it
if you're not seeing labels because they don't fit you will now see them in red. at this point you'll need to work on the labeling parameters to fit them in so they place.
if you don't see anything then something else is stopping them. things to check:
is there data in the field you're using to label?
is there a scale range present that you're outside of?
is there a sql query that has narrowed down what you're labeling?
thanks
Wendy