I play almost exclusively in UU, mainly because you can really get creative.
I noticed you're using an Espeon, so here's a tip: Have something that can baton pass Nasty Plot (like Togekiss). Get a couple of Nasty Plot boosts, then pass them to Espeon. TEACH ESPEON STORED POWER, and replace the focus sash with a Choice Scarf.
Here's a brief run-down:
- Get as many Nasty Plot boosts on your Baton Passer as possible. To this end, I recommend Togekiss for its bulk; check Smogon for a sample bulky Togekiss build. It can usually survive long enough to set up max Nasty Plot stacks if you play it right.
- Baton Pass the boosts to Espeon. Time for some maths. Stored power has a base power of 20, but increases by a further 20 for every +1 increase of ANY stat. Nasty Plot increases special attack by 2 stages, meaning that one Nasty Plot adds 40 power to Stored Power. Therefore, a maximum stack of Nasty Plot (3 uses) adds 120 power to the move, giving it a base power of 140!! But the fun doesn't stop there.
- Remember that Stored Power is a special attack, so it benefits from the special attack stat. Therefore, firstly you'll want Espeon's base special attack to be as high as possible. The higher it is, the more damage Stored Power dishes out.
Remember all those sp.atk buffs you've passed onto Espeon? As well as increasing Stored Power's base power to a whopping 140, they obviously also increase the special attack stat ITSELF. The final product is a move with 140 BASE POWER WITH A +6 SPECIAL ATTACK BOOST!!!!!! NOTHING can survive a +6 140 power move!
- Finally, invest as much speed into Espeon as possible, and give it a Choice Scarf. This practically guarantees you'll always go first with that whopping 140 power +6 move. The only real threat'll be priority moves like Shadow Sneak. I came up with this way of using Espeon myself and it's never let me down!
Final thoughts: If Togekiss is KO'd before it can pass those Nasty Plot boosts, give Espeon Dazzling Gleam and Shadow Ball for coverage, with Psychic in the last slot, because Stored Power simply isn't powerful enough on its own. Also consider baton passing some Double Team boosts as well for more survivability and even MORE power!
Here's an example of a sweep I pulled by using Espeon like this:
GT7W-WWWW-WWWA-J6EU
The problem with Choice Scarf is that this makes Espeon total bait for Dark Pokemon, especially for those running Pursuit, if it happens to get locked into Stored Power.
Just use Shell Smash + Baton Pass Gorebyss as a more reliable and consistent way for sweeping with 120 BP Stored Powers. The Attack boosts won't matter much, but they'll contribute to Stored Power's BP as well.