>>151688791 (OP)
They just need to pass out little pamphlets to let the fans know what to chant. Personally, I like the chant "FIGHT.......... AND WIN!" but some people might not know what to say so you have to write it down and put it on their seats.
Maybe have a sponsored message at ~20 minutes to reminds fans to chant? ("A reminder to Fight and WIN, Arsenal fans! Sponsored by Diet Coke" or something) Or have a "decibel meter" on the big screen and get fans to stomp their feet and clap.