Well I'm Working on at team for few battles with my cousin this summer. He's highly adaptive to all my strategies, so after I get my team figured out, I'll need help with a strategy. Here's a few pokemon I'm pretty sure I want to use. I'm using Platinum by the way. I also have access to diamond though if that means anything to you guys.
EDIT: More update.
Garchomp Lv.57 Movesetragon Rush
Mild nature Dragon Rage
Atk:173 Earthquake
Def:119 Swords Dance
Sp. Atk:138
Sp. Def: 103
Speed:138
Infernape Lv. 100 Moveset: Cut
Impish Nature Grass Knot
Atk:259 Close Combat
Def:207 Fire Blast
Sp. Atk:237
Sp. Def:183
Speed: 281
Rhyhorn Lv.23 Moveset: Rock Blast
Adamant nature Stomp
Atk:66 Fury Attack
Def:65 Scary Face
Sp.Atk:22
Sp.Def:30
Speed:22
Gallade Lv.59 Moveset: Drain Punch
Carefull nature Psycho Cut
Atk:170 Leaf Blade
Def:99 Stone Edge
Sp. Atk: 89
Sp. Def:173
Speed:117
Spiritomb Lv. 100 Moveset: Dark Pulse
Jolly Nature Psychic
Atk:219 Silver Wind
Def: 251 Embargo
Sp. Atk:197
Sp. Def:251
Speed: 115
Lucario Lv. 100 Moveset: Vacuum Wave
Brave nature Shadow Ball
Atk: 261 Calm Mind
Def: 169 Aura Sphere
Sp.Atk: 261
Sp.Def: 158
Speed:183
Hold Itemetaya Berry
A few side notes: Lucario is better now, I think.
EDIT: More update.
Garchomp Lv.57 Movesetragon Rush
Mild nature Dragon Rage
Atk:173 Earthquake
Def:119 Swords Dance
Sp. Atk:138
Sp. Def: 103
Speed:138
Infernape Lv. 100 Moveset: Cut
Impish Nature Grass Knot
Atk:259 Close Combat
Def:207 Fire Blast
Sp. Atk:237
Sp. Def:183
Speed: 281
Rhyhorn Lv.23 Moveset: Rock Blast
Adamant nature Stomp
Atk:66 Fury Attack
Def:65 Scary Face
Sp.Atk:22
Sp.Def:30
Speed:22
Gallade Lv.59 Moveset: Drain Punch
Carefull nature Psycho Cut
Atk:170 Leaf Blade
Def:99 Stone Edge
Sp. Atk: 89
Sp. Def:173
Speed:117
Spiritomb Lv. 100 Moveset: Dark Pulse
Jolly Nature Psychic
Atk:219 Silver Wind
Def: 251 Embargo
Sp. Atk:197
Sp. Def:251
Speed: 115
Lucario Lv. 100 Moveset: Vacuum Wave
Brave nature Shadow Ball
Atk: 261 Calm Mind
Def: 169 Aura Sphere
Sp.Atk: 261
Sp.Def: 158
Speed:183
Hold Itemetaya Berry
A few side notes: Lucario is better now, I think.