Some experiences to share.
a. Zoom lens around 24/70mm range are needed at funfair. Expect very tight space in 'critical' shots around VIP. Expect huge crowd at key highlights that makes movement impossible. Prime lens using leg zoom iis practically impossible then. Know the location and timing of these highlights.
b. Fast settings/fast cameras can be fun: eg dunking the vip, etc. Quite a few funfare games stalls are speed base.
c. Look out for those painted faces, clowns, mascot, etc. Go early to catch them fresh when there are less people. Catch them in the process of make up makes interesting behind-the-scene shots.
d. Many moments of glee and candids to shoot - just look out for the stalls.
e. I do not have many successes with wide shots except for very few aerial view. Head ot body shots or slightly wider give more hits.
f. Look our for colour, people who dress up, and an eye on VIP wife as well - try to bring out the funfair mood and the fun side of the human spirit
g. Flash needed in tentages esp on/even on bright days.