Co-op! The first and foremost tip is to co-op with others to get a feel of multiplayer battles. Honestly, I cannot do Joint Operation solo even if I invest a lot of resources in my character. I'm more like a co-op person who loves to play in a team, and even the game is multiplayer-focused. Not only do you learn about team plays but also the Weapon resonance effects required for a certain mode. They are buffs your character gets for equipping two characters of the same element. Quite similar to Genshin Impact's Elemental resonance. You can easily go to your character screen and check the Weapon resonance effect. Suppose you are in a team where you have to play the role of a support and heal your team. Then, it's quite good to go with double healer characters so that you can take the benefit from Benediction, a weapon resonance effect that helps you to heal more efficiently. In my experience, additional bonuses like these can sometimes make a difference in the results of a battle. So, whenever you see an item, collect it, and lastly, pay attention to details so that you don't miss out on any buffs.