If you're coming up against tough battles, then you should slow down and take your time to ensure you're doing everything you can to win. Check enemy weaknesses you aren't aware of by using moves of that type - including physical melee attacks - and if there's multiple enemies, try using moves which hit more than one demon. If you hold any attack, you'll be given a more detailed description of what it does, who it hits, and more. Take your time to learn these moves, especially if you're not familiar with SMT games, to get a leg up in the fights ahead.