The Precinct level, from my experience, is the most underrated levels of politics. Everyone is to busy looking at state and national level politics to understand that the grassroots start at the bottom. As a group, the precinct chairs are the most powerful block in any major or minor party. When ground game matters, their the guys that when motivated can make it or break it for the party or a candidate. Sadly we lose a lot when people don't want to work on the precinct level.
Here is the Precinct Level Training Manual from the Alabama Democrats
http://aldemocrats.org/images/uploads/ADP%20Precinct%20Manual.pdf