there is one thing that might give you the edge you need and you might not know: dual/triple memory appeals
if you do a memory appeal and switch the character (using L1) and then use another memory appeal (i think about 4 appeals can pass between the 2 memory appeals for this to work) both your idols will do a memory appeal together, if you switch again and do another memory appeal all 3 will do it together. the dual and triple memory appeal increase your voltage gauge much more than a single memory appeal does.
from there it is about trying out different tactics if you have trouble. festival opponents don't use their memory appeals randomly, but in a set pattern. so if you retry they will use them always at the same time (if there isn't a burst going on). let's say your opponent was able to burst a little bit before you, you can change the timing of your memory appeals to be faster than her. if you can't prevent your enemy from bursting, but either you can burst first or second, try to be first.
usually the enemy doesn't use memory appeals before the first burst happens, and if you are using sugamo and/or the reporter, you should be the first one able to burst. and often it turns into a memory appeal battle. let the enemy ust a memory appeal, then immediately counter with your own, often the enemy will use another one, then you should do a dual memory appeal, sometimes there will even be a third time. use your memory appeals AFTER your opponent, except if you need that extra boost to burst first. but as i said, sometimes that's a bit of trial and error until it works.
btw: personally i use the secret crest, but getting that one is more effort (and in fact requires you to beat a utahime-utaoji fest)
