What I'm watching the closest in this contest is polling out of Iowa because the Iowa Caucus comes first in the primary battle and the winner of the Iowa Caucus typically goes on to become the Democratic Party's nominee for president (e.g. has done so every time this century so far). Because their contest is first and sets the tone for the rest, Iowa voters also typically start tuning into the race earlier than other voters do, and in that way too can serve as an indicator of where things are going.
As things presently stand, there is a clear downward trend for front-runner and party establishment favorite Joe Biden among Iowa voters. In the most recent poll out of Iowa, he garnered 24% support among Democrats and Democratic-leaning independents, as compared with 27% in March before he declared his candidacy and 32% back in December. Moreover, this survey also indicates that his supporters are less enthusiastic than those of many other candidates. While Biden has long been christened the likely winner of the nominating battle (including by me, and also President Trump), I now have strong doubts that that will happen. He had a rocky start, launching his campaign by negotiating various scandals involving inappropriate touching and other forms of questionable behavior toward women, and he's proven since to just be a weak campaigner. He seems to be taking victory for granted and largely not bothering to campaign. He holds few rallies compared to many of his top rivals and doesn't attend town halls, for example. He also finds himself changing positions on issues abruptly (as in the recent case of the Hyde Amendment), which detracts from his vital image as an honest and authentic person, which has been heralded as his main asset. And then there's been just cringe-inducing stuff like the now-infamous Biden-Barack friendship bracelet and even former Obama advisor David Axelrod found to be too much in the way of naked ass-kissing.
Looking at all this, one begins to recall why Biden performed so poorly the last two times he ran for president. I hereby predict that he'll bomb in the upcoming debate and wind up as sort of the Jeb Bush of this contest.
I really think the first debate will shake things up because while these rallies and town halls may get hundreds, thousands, or even hundreds of thousands of observers, the fact is that the first debate in any given nominating battle is always the single most-viewed event thereof; tens of millions of Americans will tune in. THAT is enough to shake up the race fundamentally, and I think it will. It's impossible to predict who will actually win the nomination at this early stage, but were I a betting person (and admittedly there's a reason I'm not), I'd bet that the most likely person will be Pete Buttigieg. He's more or less in the same lane as Joe Biden ideologically, but has the ability to draw in younger, more enthusiastic voters. He also just comes off as way more competent.
The candidates I'm the most interested in personally are Elizabeth Warren (mainly for her economic policy ideas) and Marianne Williamson (mainly for her foreign policy ideas), though I tend to doubt that either (especially Williamson) will emerge victorious. I also dislike Williamson's lack of governing experience, but just find her to be a unique and interesting candidate nonetheless. Elizabeth Warren has a tremendous ability to communicate complex and detailed policy positions in a way that is clear and easy to understand. It's a quality that makes her a good teacher, and I think that's something we need right now, in addition to a lot of the actual ideas that she stands for.