Okay, so i have been into Pokemon since Gen 4, but only with the release of X and Y and i got into competitive battling. I am not so good yet but i hope to get better. My team is as follows:
ShadowKing (Gengar)
EV's: 252 Atk, 252 Spd, 4 HP
Nature: Timid
Item: Focus Sash
Ability: Levitate
Moveset:
Shadow Ball
Thunderbolt
Dazzling Gleam
Taunt
So, basically Gengar is my Anti-Lead. He is immune to fake out and carries taunt for Trick Room teams, PerishTrap teams etc. T-Bolt is great for surprising people and hitting water and flying types for super effective damage. Shadow Ball is a strong STAB and Dazzling Gleam is good for cleaning up.
ShadowQueen (Gardevoir)
EV's: 252 HP, 116 Def, 140 SpAtk
Nature: Modest
Item: Assault Vest
Ability: Trace
Moveset:
Shadow Ball
Moonblast
Psychic
Focus Blast
Gardevoir is a tank who will almost always survive one hit, and will almost always OHKO. With this investment, she can take Talonflame's Choice Banded Brave Bird (86% chance). Shadow Ball is really nice for other psychic types and ghost types. Moonblast and Psychic are basic STAB's, and focus blast has great coverage overall.
ChildKiller (Mawile)
EV's: 252 HP, 156 SpDef, 100 Atk
Nature: Adamant
Item: Mawilite
Ability: Intimidate -> Huge Power
Moveset:
Swords Dance
Sucker Punch
Play Rough
Protect
Mawile is so powerful that he doesn't need full investment to OHKO easily. The bulk investment lets him tank hits easily. Swords Dance boosts his attack to ridiculous levels, Sucker Punch is priority, Play Rough is immense STAB, and protect is kinda standard. Nothing particularly different from other Mawile sets.
Edward ScissorHands (Mienshao)
EV's: 252 Atk, 252 Spd, 4 HP
Nature: Jolly
Item: Life Orb
Ability: Reckless
Moveset:
High Jump Kick
Fake Out
Quick Guard
Wide Guard
Mienshao is great. Fake out is so good in doubles, as are Quick and Wide Guard. Also, his Reckless boosted High Jump Kick is INSANELY good. It will 2HKO a full Defense and HP invested Skarmory after Leftovers recovery. I think i have said enough!
ShadowBEAST (Tyranitar)
EV's: 252 Atk, 252 HP, 4 SpDef
Nature: Adamant
Item: Lum Berry
Ability: Sand Stream
Moveset:
Rock Slide
Crunch
Brick Break
Protect
T-Tar is basically my only Talonflame counter, as well as being an all round tank and beast. Rock Slide hits Talonflame and MegaZard Y for quad damage, crunch is a second STAB, and brick break destroys screens as well as surprising other T-Tars and things like Bisharp and Weavile. Lum over Sitrus Berry because once he is statused he struggles.
Nickname Ideas? (Salamence)
EV's: 252 SpAtk, 252 Spd, 4 HP
Nature: Timid
Item: Yache Berry
Ability: Intimidate
Moveset:
Hydro Pump
Flamethrower
Draco Meteor
Protect
Sooo, special intimidating Salamence fits perfectly into my team, the Yache Berry lets him survive most hits, Hydro Pump and Flamethrower are great coverage and Draco Meteor is immense STAB. Salamence is just amazing so yeah, cant think of anything else to say.
So there is my team, hope its good, hope there is good advice!

ShadowKing (Gengar)
EV's: 252 Atk, 252 Spd, 4 HP
Nature: Timid
Item: Focus Sash
Ability: Levitate
Moveset:
Shadow Ball
Thunderbolt
Dazzling Gleam
Taunt
So, basically Gengar is my Anti-Lead. He is immune to fake out and carries taunt for Trick Room teams, PerishTrap teams etc. T-Bolt is great for surprising people and hitting water and flying types for super effective damage. Shadow Ball is a strong STAB and Dazzling Gleam is good for cleaning up.

ShadowQueen (Gardevoir)
EV's: 252 HP, 116 Def, 140 SpAtk
Nature: Modest
Item: Assault Vest
Ability: Trace
Moveset:
Shadow Ball
Moonblast
Psychic
Focus Blast
Gardevoir is a tank who will almost always survive one hit, and will almost always OHKO. With this investment, she can take Talonflame's Choice Banded Brave Bird (86% chance). Shadow Ball is really nice for other psychic types and ghost types. Moonblast and Psychic are basic STAB's, and focus blast has great coverage overall.

ChildKiller (Mawile)
EV's: 252 HP, 156 SpDef, 100 Atk
Nature: Adamant
Item: Mawilite
Ability: Intimidate -> Huge Power
Moveset:
Swords Dance
Sucker Punch
Play Rough
Protect
Mawile is so powerful that he doesn't need full investment to OHKO easily. The bulk investment lets him tank hits easily. Swords Dance boosts his attack to ridiculous levels, Sucker Punch is priority, Play Rough is immense STAB, and protect is kinda standard. Nothing particularly different from other Mawile sets.

Edward ScissorHands (Mienshao)
EV's: 252 Atk, 252 Spd, 4 HP
Nature: Jolly
Item: Life Orb
Ability: Reckless
Moveset:
High Jump Kick
Fake Out
Quick Guard
Wide Guard
Mienshao is great. Fake out is so good in doubles, as are Quick and Wide Guard. Also, his Reckless boosted High Jump Kick is INSANELY good. It will 2HKO a full Defense and HP invested Skarmory after Leftovers recovery. I think i have said enough!

ShadowBEAST (Tyranitar)
EV's: 252 Atk, 252 HP, 4 SpDef
Nature: Adamant
Item: Lum Berry
Ability: Sand Stream
Moveset:
Rock Slide
Crunch
Brick Break
Protect
T-Tar is basically my only Talonflame counter, as well as being an all round tank and beast. Rock Slide hits Talonflame and MegaZard Y for quad damage, crunch is a second STAB, and brick break destroys screens as well as surprising other T-Tars and things like Bisharp and Weavile. Lum over Sitrus Berry because once he is statused he struggles.

Nickname Ideas? (Salamence)
EV's: 252 SpAtk, 252 Spd, 4 HP
Nature: Timid
Item: Yache Berry
Ability: Intimidate
Moveset:
Hydro Pump
Flamethrower
Draco Meteor
Protect
Sooo, special intimidating Salamence fits perfectly into my team, the Yache Berry lets him survive most hits, Hydro Pump and Flamethrower are great coverage and Draco Meteor is immense STAB. Salamence is just amazing so yeah, cant think of anything else to say.
So there is my team, hope its good, hope there is good advice!