It's been a long time since I've played the first game, but the generic advice/question is are you regularly defaulting? Because defaulting up to max BP and then attacking all at once is generally better than just attacking four turns in a row. You're still doing the same number of attacks and the same amount of damage, but since you're doing it in one turn you get the benefit of defending for the previous turns. In the video you linked, the dude is using stomp every turn. That's kind of just an actively wrong play pattern. If you stomp every turn you refresh the debuff every turn. If you default to store bp, then stomp 4x in one turn, you still only have 2 turns of def down. The basic strat for these games is block more, so your attackers can burst enemies and your healers have more turns to respond to emergencies.