New to competitive Pokemon, here's my first team

[LzzzR]

Hi, I'm LzzzR!

I finally made an account here and decided to give competitive Pokemon a shot. I've been lurking for years, from the very beginning of 4th generation. I guess this makes me a bit too reliant on theoryfighting.
What I got here is my very first serious competitive team, the best one I could come up with. It wasn't easy, I think teambuilding is easily the hardest part of Pokemon. I've played with it a bit and it feels like it has some flaws as Azumarill and Skarmory have usually mean't an easy win for the opponent. Same goes for statboosters like Shell Smashers or Volcarona. Once they get going there is no stopping them.

Let's get to my team then...

Cloyster @ White Herb
Ability: Skill Link
EVs: 4 HP / 252 Atk / 252 Spd
Jolly Nature
- Shell Smash
- Icicle Spear
- Rock Blast
- Ice Shard

Cloyster is my favorite. If I had to leave one it would be him. I'd like that team that would be able to support Cloyster well and allow him to sweep.
I've chosen Jolly nature because I want to be as fast as possible because Cloyster doesn't like to take those special hits, losing his sweep. I don't mind priority moves that much because Cloyster has huge defence and I am running White Herb, but I don't think it's helping me against CB Bullet Punch from Scizor.
For the last moveslot I've chosen Ice Shard to beat those weakened priority users and it's helpful against faster opponents when I haven't had the opportunity to Shell Smash yet. This makes me absolutely free against Steel types though and that kinda sucks.

Forretress @ Leftovers
Ability: Sturdy
EVs: 252 HP / 252 Def / 4 SpD
Relaxed Nature
IVs: 0 Spd
- Rapid Spin
- Stealth Rock
- Volt Switch
- Gyro Ball

With Cloyster being weak to every hazard out there I need to have a spinner. He is obviously my pokemon for setting my Stealth Rock too.
In my matches I've had amazing success with him as a spinner, but other than that he has been rather useless. Maybe there are better alternatives than him? I think he is the weakest in my team at the moment.

Aegislash @ Life Orb
Ability: Stance Change
EVs: 4 HP / 252 Atk / 252 SAtk
Quiet Nature
- Shadow Ball
- Iron Head
- Sacred Sword
- Shadow Sneak

This guy deals some amazing damages and breaks most walls thrown at me. He still loses badly to Skarmory which is annoying. This set doesn't need King's Shield as I hit them once and switch away. It's amazing ability allows him to switch in easily with his great defences. It's a shame everyone is carrying Earthquake. I tend to overestimate his defence too and keep forgetting Steel doesn't resist Dark or Ghost in 6th gen anymore.

Gyarados @ Leftovers
Ability: Intimidate
EVs: 156 HP / 72 Atk / 96 Def / 184 Spd
Adamant Nature
- Dragon Dance
- Taunt
- Waterfall
- Stone Edge

The old BulkyGyard set. Is it still usable these days? I think maybe I could run another set or swap him for something else. It feels like he isn't needed in the team with Cloyster around handling the strong Physical attacker role. I taunt to stop certain Pokemon and Dragon Dance on the switch. Just the bread and butter stuff really.

Gliscor @ Toxic Orb
Ability: Poison Heal
EVs: 244 HP / 252 Def / 12 Spd
Impish Nature
- Protect
- Substitute
- Toxic
- Earthquake

Gliscor is most of the time my lead and he has done a decent job at it. He is very to hard to take out with Poison Heal and smart use of protect, but the lack of a way to hit flying types seriously hurts. Especially Skarmory. If I can't poison them I'm usually screwed. I've noticed that this set works surprisingly well against MegaGengar.

Sylveon (F) @ Leftovers
Ability: Cute Charm
EVs: 252 HP / 4 Def / 252 SDef
Bold Nature
- Wish
- Protect
- Moonblast
- Toxic

My special wallish... thing... She has done a decent job at that but is total setup bait as she can't deal any damage. Wish has saved me many times too. She is quite good at walling not super strong special attackers, but if they run Calm Mind my game is over immediately.



I feel like my team is very limited currently, but when it gets the momentum it plays very well. It just can't handle phazers or steel types very well. And especially the set up pokemon. My only counter for that is Gyarados's Taunt and he isn't really fit for that role.
As for improving my team I am pretty much clueless, I just don't know what is worth replacing for something else. I've also used really common sets for my pokemon as I don't think I should start making my own sets until I get experience.

Any feedback and help is appreciated. Thank you for your time.

 

[Ze Kaiser]

Just a quick note, although not strictly required, a mega pokemon would probably benefit your team greatly. If you do choose to use a mega you could always just use your Gyarados although their are plenty of other viable options as well.
Edit:
Just a few more things- an excellent rapid spinner to replace Forretress would be Excadrill with an air balloon(he was uber last gen and that set still works nicely now in OU), I like Gliscor, Aegislash and Cloyster, Gyrados I'm not sure(mega slot maybe?), and Finally Sylveon who I find very average and I feel you dont need a special wall so much as a special attacker. My recommendation? Why not switch Sylveon out with his older brother Espeon, i know you lose the new nifty fairy type but Espeon can be a boss sweeper/tank with this set:
Espeon Leftovers, Magic Bounce
Moves: Calm Mind, Stored Power, HP Fighting, I have wish in this slot but you could always replace it with Reflect, Light Screen, Baton Pass etc.
EVs: 252 Hp, 252 Def, 4 SpD
With this set Espeon can back bounce hazards, take hits, all while setting up with Calm Mind before unleashing the monster that is stored power(3 calm minds can OHKO a Scizor)
If you dont want Espeon or Sylveon yet want to retain the Fairy type you have some options: Mega Mawile, Prankster Klefki, Florges etc.
I hope I helped this was my first time rating keep it up and Good Luck!

 

[YellowRice]

First of all, your Sylveon is running a full defensive spread. As you already have Gliscor and Gyarados, you want Sylveon running 252 special defense, 4 def instead. Also, to take care of set up pokemon, its almost critical to have a phazing move or a status move. On Sylveon, toxic is a must. That should give you a better defensive core in combination with your other bulky pokemon.
Next, your Forretress. It is useless, especially with the attack EV's you are running. Gyroball is standard, but earthquake? Toxic is a much better move, and so is volt switch for momentum to switch into an offensive threat or counter. As you already have two toxic users (assuming you change shadow ball to toxic on Sylveon) I'd say your Forretress can be replaced. Unfortunately, this would mean you'd have to replace another pokemon as well to make up for the stealth rocks and rapid spin if you want both. Therefore, unless you want to make big roster changes, at least switch up your EV's and slap on volt switch.
Lastly, your team needs a way to deal with teams that have Skarmory in their wall core. You don't have a strong special attacker, and Aegislash with a shadowball doesn't cut it because it can't OHKO Skarmory and it has plenty of chances to roost on your other pokemon like Gliscor, Sylveon, and Forretress (which is why you run volt switch). I personally would look into some special attacking mega evolutions as your team lacks one, and they are very strong wallbreakers. Another alternative would be to run a choice scarfer, because your team lacks a fast revenge killer as well.

 

[LzzzR]

I removed Attack EVs from Forretress and moved it all to Defence. Replaced Earthquake with Volt Switch.

Maxed SpD for Sylveon instead of Def as you suggested and replaced Shadow Ball with Toxic.

Thank you for your help so far. I'm just wondering could Calm Mind work instead of Toxic for Sylveon? She is supposed to be a special wall so being able to boost could make her scarier than right now and adding more Toxic to my team is not going to help much against Steel types.

Going to try out the slightly updated team and see how it feels.