Dream Mirror has gotten a lot of flack (justifiably) for being pretty bricky and gimmicky. But Dream Mirror has recently gotten a new support which makes it a hundred times better than what it used to be.
I'm going to cut it short here. Your main strategy is on a 1 and 2 card combo. Having either Neiroy, The Dream Mirror Heretic or both Neiroy and Chaos Creator
You use Neiroy to get it's LIGHT counterpart onto the field > Special Summon Sprite onto the field and add Dream Mirror of Chaos to your hand (and if it's already there) add Morpheus, The Dream Mirror White Knight > Then activate Dream Mirror of Terror and use Sprite's effect to summon Mara to Special Summon a monster from your hand > Then link Mara and Neiroy into Artifact Dagda or Anaconda. > Then fusion summon Tormentor. If you have Chaos Creator, special summon it before using Anaconda's effect. From there you can go into many other combos which you'll most likely figure out on your own. Good luck Duelist and I hope you have fun with this deck and shock people with your Dream Mirror plays!