Print your state laws about voting and know them inside and out.
Watch carefully for people voting for the homeless drunks.
Keep an ear to the check in. The clerks want people to vote since it’s easier that way. Listen for those who have already voted and people who are not registered. Insist that they vote provisional ballot if you’re in a 75 percent dem area. Anything less than 75 percent requires on the spot decisions on whom to challenge.