First mass attack tips?

Hi! This is my first year joining art fight and I'm still learning the ropes of this!

I'm working on doing my first "mass" attack and I'd like to know if there's something I should watch out for or keep an eye out for. Of course, I'm already reading all the dos and don'ts of each artist regarding their characters, but I'm just wondering if there's something else, just so I make sure I'm extra careful.

Also, I don't know if I'm using the right flair for this, let me know if it's not! :]