Need advice on working election polls

Hello DU'ers,
Municipal elections (county commissioners, school board and city council positions) are going on at our locality this weekend. The county elections polling workers coordinator knew i'm bilingual so she called me to ask if i'd be willing to be on call for emergency work in the case one of their assigned workers drop out. Given i feel a bit guilty about turning her down the last time she called several months ago and the fact i don't really have anything pressing this Saturday i said yes (so my conscience will stop bothering me). That and the fact I am also very curious as to how workers can "cheat", and if there are any gaps in the system/process i can identify.

Anyhoo, need advice on what to watch out for, when best to take a break, etc. as she's told me the hours will be long - 6am to 6pm, possibly extending to 8pm depending on turnout.

Thank you and hoping our local Democratic candidates will kick butt!!
One Texan