It's already there for a while now, how to behave still not change, stay low and slowly improve your character along its stage.
Most easiest way to keep up with this is, make sure your girls that need to run each stage have their Rank at least (Stage level - 1) before finish its whole chapter. Unless it's on early chapter that you cannot find certain item, then you just have to make sure you can find most of them, equip them --and you'll be safer on public eyes.
On stage 8 it's highly recommend that you would have your girls avg.level at least 65 before you can finish 8-12 to unlock [Princess Arena] where Lv.65 NPC teams looks to be their standard.
Also, quick notice, DMM version are now 1.5.1