Help with OU team

[BigYak]

Hi, I'm pretty new to teambuilding and was wondering what else I could add/change to improve this Singles Team:

 

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Milotic - Leftovers

 

EVs: 252 HP - 252 Def - 4 SpA

 

Moveset:

Scald

Recover

Haze

Mirror Coat

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Ferrothorn - Leftovers

 

EVs: 252 HP - 208 SpD - 48 Def

 

Moveset:

Gyro Ball

Stealth Rock

Leech Seed

Spikes/Power Whip?

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Garchomp - Life Orb

 

EVs: 252 Atk - 252 Speed - 4 HP

 

Moveset:

Earthquake

Dragon Claw

Fire Fang/Crunch?

Swords Dance

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That's it from there, as far as I know the three above should work well together due to resistances and decent coverage

 

Now I'm stuck on any additions to the team. Help pls? :)

[Alrena]

I'd swap out Mirror Coat for Ice Beam to deal with Chomps. If you're planning to Swords Dance on Garchomp you'll have to get support to kill mons that punish him for SDing. Something like a Magnezone to trap steels trying to wall him would be good too. Depending on the rest of your team you can pick between Spikes or Power Whip.