Time keeper question

[rbmartin]

I am a High School official in other sports but not in football. Last night, I was drafted on short notice to run the clock/scoreboard for my son's Jr. High football game (FED rules). Fortunately, the game went well (other than ending in a 6-6 tie) but I felt a little unprepared.
My question is, other than the "start the clock" & "stop the clock" signals, what do you officials expect a good timekeeper to be looking for during a game. How can I best educate myself to do this job properly.