texhnolyze
Banned
Just relying on character tier isn't enough. As great as having a 5* takumi is he'll still get bodied by a 5* Robin or hell maybe even a 4* Kagero. Do deal with chapters you either have to have a team that hard counters the enemy setup, or a generic team that can handle all threats. Abuse the weapons triangle as much as possible.
To go beyond that you also need to look at the skills your team has. Do they synergize well. Do you have ally buffs that buff your teams main strengths or do you have movement skills that can help you get into position to take out more enemies.
Check the hard modes for earlier maps. Some of them have lower level requirements than the later normal chapters.
Thanks, I'll keep those in mind.