If you look at the early voting/caucusing states, one thing is clear. Hillary is the clear leader in most of them.
When it comes to Iowa, though she isn't yet leading yet in most polls, she is steadily gaining. I think it is most helpful and relevant to watch the same polling orgainzation over time to see how the candidates are trending.
Strategic Vision has been polling Iowa regularly this year. They have 5 polls to compare. Here is the data:
Having watched all three debate/forums it pretty clear that the more people see Hillary Clinton, the better they like her. I can't say that I'm one of the converted, I have always thought Hillary is great and have been a supporter from the beginning. It's good to see that more people are coming to see the person and candidate that I've seen for years.