Go to the Properties tab, All Properties, and compute the title property of the Subject field (the mouse over hover text).

I'm not sure what the text size limit is for that, but you could truncate the Body so you're only showing the first part of it.  Then, if it looks interesting enough, the user can click on the document to read the rest.

Remember, if the Body is rich text, then you'll need to get the text property of the field for the display.