How can I improve these teams?

Sand Storm Team!

Hippowdon (F) @ Leftovers
Ability: Sand Stream
EVs: 252 HP/6 Atk/252 Def
Impish nature (+Def, -SAtk)
- Earthquake
- Stealth Rock
- Slack Off
- Roar
---
Empoleon (M) @ Leftovers
Ability: Torrent
EVs: 252 HP/6 SAtk/252 SDef
Calm nature (+SDef, -Atk)
- Surf
- Stealth Rock
- Grass Knot
- Ice Beam
---
Jirachi @ Leftovers
Ability: Serene Grace
EVs: 252 HP/80 Def/176 Spd
Bold nature (+Def, -Atk)
- Calm Mind
- Substitute
- Thunderbolt
- Psychic
---
Scizor (M) @ Life Orb
Ability: Technician
EVs: 32 HP/252 Atk/224 Spd
Adamant nature (+Atk, -SAtk)
- Bullet Punch
- Aerial Ace
- Swords Dance
- Roost
---
Skarmory (M) @ Leftovers
Ability: Keen Eye
EVs: 252 HP/96 Atk/162 Def
Impish nature (+Def, -SAtk)
- Brave Bird
- Spikes
- Whirlwind
- Roost
---
Tyranitar (M) @ Leftovers
Ability: Sand Stream
EVs: 252 HP/72 Spd/186 SAtk
Quiet nature (+SAtk, -Spd)
- Substitute
- Focus Punch
- Flamethrower
- Dark Pulse
---

Idk Team!

Ambipom (M) @ Life Orb
Ability: Technician
EVs: 6 HP/252 Atk/252 Spd
Jolly nature (+Spd, -SAtk)
- Fake Out
- U-turn
- Brick Break
- Payback
---
Dusknoir (M) @ Leftovers
Ability: Pressure
EVs: 252 HP/76 Def/180 SDef
Careful nature (+SDef, -SAtk)
- Thunderpunch
- Shadow Sneak
- Will-o-wisp
- Pain Split
---
Milotic (F) @ Leftovers
Ability: Marvel Scale
EVs: 252 HP/234 Def/24 SAtk
Modest nature (+SAtk, -Atk)
- Surf
- Ice Beam
- Rest
- Sleep Talk
---
Venusaur (M) @ Leftovers
Ability: Overgrow
EVs: 252 HP/6 Spd/252 SDef
Calm nature (+SDef, -Atk)
- Sleep Powder
- Leech Seed
- Energy Ball
- Sludge Bomb
---
Umbreon (M) @ Leftovers
Ability: Synchronize
EVs: 252 HP/252 Def/6 SAtk
Bold nature (+Def, -Atk)
- Mean Look
- Wish
- Baton Pass
- Toxic
---
Weavile (M) @ Focus Sash
Ability: Pressure
EVs: 2 HP/254 Atk/254 Spd
Naive nature (+Spd, -SDef)
- Ice Punch
- Night Slash
- Brick Break
- Fake Out
---