I quite understand the mistakes the Hillary Campaign made, when all the data is showing you're doing all the right things. Not just her internal data, but all data.
Maybe it's a good thing to take a step back once in a while during the campaign, and wonder where you can compensate for possible mistakes and overlooked dangers. But when every minute, dollar and campaign stop counts in the final stretch of the campaign, I understand why they followed the strategy that by all accounts meant them winning the election.
I do fault her though for pulling the race card as much as Trump did. Her campaign stressed the diversity and inclusiveness too much (I know, it shouldn't be a bad thing), and the moral superiority over Trump ("think about our kids") that it kind a burried the other important issues of the election, like the economy or security. People are selfish, and their own safety and economic security goes before that of others. When the Nevada early voting story with record Latino turnout broke, I didn't see that as a possitive. It dominated the news for days, yet I was sure the midwest/northern states couldn't give a rats ass about that. If anything, the focus on what kind of voter turned out (color of their skin), probably annoyed many white voters. You can call it racist, but I'm sure a lot of those could have been swayed by a more economic message, even if it came from a black or hispanic candidate, democrat, woman, ...
What amazes me more, is not that Hillary lost despite doing all the "right things", but that Trump won despite doing all the "wrong things". His campaign was an absolute clusterfuck. I don't know if his intuition is really that good, or if he made a high risk gamble that paid off, or if he is just super lucky, but he got his 270 electoral votes. He even lost the popular vote, but managed to max out his margins in the right places to get those states. Seeing it unfold on election night is still one of the most surreal things I've ever witnessed.