Med Gunner with 1111's best friend is her Forward Aerial. She'll need to approach with it and escape situations with it, I like to use it to back off from an opponent to starting using Charged Shot. I'm also a fan of just rushing in and trying to land Up or Down Smash / Tilt when sliding behind my foe. Don't use that too often, as it'll get pretty obvious when you'll try to do it. Also an excellent tool to juggle opponents and to use when you getting up from the ledge.
If your opponent has a reflector you could try to bait them to reflecting Charged Shot and you reflect it back at them, most people probably don't realize Gunner has one herself and you can definitely surprise someone if you don't use it anytime before you bait out their reflector.
Using Charged Shot in succession with Flame Pillar usually works too I think, if you have a fully charged one and you catch someone with Flame Pillar it should usually connect. Don't forget to use Flame Pillar to cover ledges too, after your opponent's invincibility wears off Flame Pillar will knock them off of the ledge, in a perfect placement for a Charged Shot heading their way. You could additionally run up and try to hit them with your Down Aerial or Back Aerial, Neutral Aerial works too but the other two can kill (especially if you land the spike on the Down Aerial).
Lunar Launch's projectile can stage spike if you face away from the stage, but I believe a fair amount of attacks can clang it. If you're landing and your opponent is nearby you can use it to cause an explosion to cover you while you land, but if you miss the timing you'll be sent back up. Thankfully the move's knockback trajectory should send them a far away enough for you to land safely if they're not at 0% or something. You could even use it as a kill move off stage if you're facing the stage and your opponent is decently near the blast zone.
As for your Reflector, it's good at reflecting your own Charged Shot if you bait your opponent's out like I said. You could additionally use it in the air to look the other way so you can use your Forward Aerial to recover, but I don't recommend this unless you're high above the stage. Use it too low and you may not be able to get back up to the ledge if the stage is a floating platform. Not much else utility for it aside for being a mediocre get off me, lol.
Hope this helps a bit.
