how can i improve my OU team?

[rubyy]

my current team is the following listed below. However i feel it is slightly too offensive and also i was thinking about swapping out forretress for a staller like breloom or a better wall thats more well rounded like dusclops or registeel. how ever i have been working on this team for a while and really like how its coming along any feed back that you guys think would help would be much appreciated.

1) Starmie
Nature: Timid
EVs: 252 SpA/252 Spe
Item: Life orb

MOVES:
-hydro pump
-thunderbolt
-icebeam
-recover


2) Forretress
Nature: Relaxed
EVs: 252 HP/ 252 Def
Item Custap Berry

MOVES:
-rapid spin
-spixes
-toxic spixes
-gyro ball


3) Tyranitar
Nature: carefull
EVs: 252 HP/ 76 Atk/ 180 SpD
Item: leftovers

Moves:
-stealth rock
-stone edge
-superpower
-crunch


4) Lucario
Nature: Adamant
EVs: 252 Atk/ 252 Spe
Item: black belt

Moves:
-close combat
-sword dance
-extreme speed
-blaze kick


5) Garchomp
Nature: jolly
EVs: 252 Atk/ 252 Spe
Item: Choice Scarf

Moves:
-Outrage
-Earthquake
-Fire Fang
- duel chop


6) Sigilyph
Nature: Bold
Evs: 252 HP/ 200 Def/ 56 Spe
Item: Flame Orb

Moves:
-Cosmic power
-Stored Power
-Roost
-Psycho Shift

 

[OscillatingOcelot]

I wouldn't call myself the best competitive battler, but if we're talking OU, Ferrothorn, Jellicent, and Hippowdon are all good walls to consider.

Ferrothorn is well rounded in the sense that its base defense and special defense are about the same. Despite 4x weakness to fire, I've survived some non-stab fire moves because its defense is just that high. Most movesets have one offensive move so it isn't complete taunt bait, and can throw around Thunder Wave which is pretty useful. Chansey and Blisseys are frankly really annoying, but Ferrothorn can sap massive amounts of health out of them with Leech Seed which will still occur if you switch out to a pokemon that is better equipped to KO Chansey/Blissey. Ferrothorn can work on both rain teams (Makes fire attacks against it far less dangerous), and sandstorm teams thanks to steel typing. These are just a few examples of many where Ferrothorn is just stupidly good, but can still be dropped by either a good fire/fighting move or a pokemon that was allowed to set up beforehand. My Ferrothorn isn't used to set up entry hazards but it does have access to Spikes and Stealth Rock as well if those interest you. Ferrothorn pretty much always performs well as long as the rest of your team can support its fire/fighting weakness.

Hippowdon is pretty good if you have other pokemon that work well in Sandstorms, like Ferrothorn. Several of your pokemon not only already have typing to prevent sandstorm damage but interact very well with sandstorms. Garchomp can have Sand Veil while Tyranitar can wall special attacks in sandstorms, which it already causes on its own because it too has Sand Stream. It can learn Ice Fang if you want to surprise dragons, but not necessary for a solid move set. Great physical wall but remains exposed to special attacks that it is weak against (High investment in special defense EVs will help though).

If you're looking for a more special oriented wall then Jellicent is another good OU tier wall (Last I checked anyway) with great typing. Although it only has passable physical defense, it can compensate for this by inflicting a burn either through Will-o-wisp or Scald (You can neuter dangerous physical attackers even if they manage to get a swords dance off this way), and rarely ever has trouble hitting pokemon for at least neutral damage between Scald, Surf, and/or Shadow Ball. Ice Beam can also work, and it is capable of wearing down opponents with Toxic as well. It is extremely easy to switch into Jellicent, and because I open with a pokemon that is severely weak against fire it compliments fire weak pokemon extremely well (Many of which are coincidentally also weak to fighting, which Jellicent is immune to). Taunt is an option if you have room for it but I personally don't have a build with Taunt in it. The only move that I would consider mandatory is Recover, for obvious reasons. Overall Jellicent is probably my personal favorite wall.

If you're willing to go into lower tiers, there are more underused walls like Bronzong too, but these three are pretty solid walls/stallers for the most part.

Edit: Forgot Skarmory, and probably others, but he is pretty awesome as well.