She actually put a lot of effort into turning out voters in Florida's urban areas (especially South Florida), and she was also able to leverage her husband's ties to the state to her advantage. She did better than Obama in the urban areas of the state; it's the suburban/exurban areas (especially in and around I-4) that gave the state to Trump.
Imagine if she won Florida with the rest staying the same. Trump would still have won with 277 electoral votes then. But it would have blown anybody's mind in the summer and fall of 2016 to think about Clinton winning Florida while losing the election. It was actually believed that once the state is called for her early into the night, the whole thing is just over.
