Key findings from early exit polls (note exit polls have historically missed reasonably often... do not rely on these findings too much):
voters feel better about the national economy (only 62% say it is some degree of bad) than they did in either 2008 (93%) or 2012 (76%), which is generally good for the incumbent party
voters also feel somewhat better about their own family's finances compared to 4 years ago (+3) than they did in 2012 (-8), which is also generally good for the incumbent party
also finding 37% democrats, 32% republicans, 31% independents (2012 was 38, 32, 29, so little change, though it is in favor of republicans - but not enough to overcome 2012's margin without Trump doing significantly better among independents than Romney did, especially if Trump underperforms with registered Republicans)
finding Obama with 54% approval on election day, ie if people view Hillary as more Obama, she's got a pretty high ceiling
and finally, as evidence to Trump potentially underperforming Romney... exit polls have white college educated men as only +11 for Trump. Past 4 elections they have been +23, +20, +14, and +21 for the GOP