First note: I am now using InDesign CC.
Before we export to ePub from InDesign, there are some import issues to understand. To get the best results for the ePub, we must be sure to provide appropriate tags for paragraph, character and object styles.
We do this through the 'Export Tagging' panel of each of the style dialogues. This is also where we decide how InDesign will split the ePub.
Fo our convenience we can set all of these together through the 'Edit all Export Tags Panel'.