Battle frontier brain team strategies

[Pikachu!]

I'm new to competitve battling and having trouble taking down the frontier brains.
Currently, I have all the silver prints, but, when I try to go further, i get pwned to death by everything there.
Here's what I use for every facility:
Battle tower:Electivire(lead)
Expert belt
Adamant
252 atk,252 spd
Thunderpunch,ice punch, cross chop, earthquake
Flygon
choice band
Adamant
252 Atk, 252 spd
Earthquake, outrage, U-turn, fire punch
Dusknoir
Leftovers
relaxed
252 def, 252 sp.def
Gravity, dynamic punch, will-o-wisp, pain split

Battle roulette, batlle castle:Dusknoir(lead)
Relaxed
252 def, 252 sp.def
trick room, will-o-wisp, painsplit, shadow punch
Dragonite
jolly
252 atk, 252 speed
dragon dance, outrage, earthquake, fire punch
gengar
timid
252 sp.atk, 252 speed
shadow ball, thunderbolt, focus blast, explosion

Battle arcade: Dragonite
Lum berry
Adamant
252 atk, 252 sp.def
Dragon dance, outrage, thunder punch, ice punch

So there you have it, there's my teams, if it wouldn't be much of a hassle, could someone give me tips on how to get farther than the first brain match.
By the way, obviuosly i didn't post a battle factory team cause i have no choice about the pokemon there.

 

[Staraptor Call]

There's already a thread for this.