One thing I've noticed is Rasmussen is leading the other pollsters by about a month, so I'm keeping an eye on him.
Not the biggest individual poll guy, but the latest polls have been Likely Voters and larger samples, and the aggregate Biden lead is trending down.
Usually that doesn't happen till sometime in the first half of October if the Republican looks to win, and it reflects little things I've noticed here and there for the last month or so.