VGC Beginner's team

[TGX300]

Hello everyone!
I have never really made a VGC team before and not sure what I'm doing, but any criticism is well-welcome.

Landorus-Therian @ Groundium Z
Ability: Intimidate
Shiny: Yes
EVs: 4 HP / 252 Atk / 252 Spe
Jolly Nature
- Earthquake
- Rock Slide
- Knock Off
- Protect

This is most common Poke.

Tapu Koko @ Magnet
Ability: Electric Surge
Shiny: Yes
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
- Thunderbolt
- U-turn
- Hidden Power [Ice]
- Taunt

Cresselia @ Iapapa Berry
Ability: Levitate
EVs: 252 HP / 4 Def / 252 SpA
Modest Nature
IVs: 0 Atk
- Trick Room
- Psychic
- Icy Wind
- Helping Hand

Charizard @ Charizardite Y
Ability: Blaze
EVs: 4 Def / 252 SpA / 252 Spe
Timid Nature
- Heat Wave
- Solar Beam
- Overheat
- Protect

Kartana @ Focus Sash
Ability: Beast Boost
Shiny: Yes
EVs: 4 HP / 252 Atk / 252 Spe
Jolly Nature
- Leaf Blade
- Sacred Sword
- Tailwind
- Detect

Stakataka @ Choice Band
Ability: Beast Boost
Shiny: Yes
EVs: 252 HP / 252 Atk / 4 SpD
Lonely Nature
IVs: 14 Def / 0 Spe
- Earthquake
- Gyro Ball
- Iron Head
- Rock Slide

I'm not sure what to do with the end-game sweeper.

Please help, thanks!

 

[IronBullet]

Welcome to Smogon! I'm locking your RMT for the time being as the forum rules require that you provide in-depth descriptions for each Pokemon to explain their roles. Please read the rules carefully and take a look at Team Showcase to see the level of detail we require. PM me with updated descriptions and I'll be happy to unlock this.