The Mighty Tyranitar build is a high-damage output physical attacker. Its strategy is to use Focus Energy to raise its critical hit chance and then use moves like Stone Edge and Shadow Claw to take out your Pokémon. It also has the moves Crunch and Earthquake for extra coverage. It will also use Dragon Dance to raise its attack at pre-programed times during the fight.
Many builds people have been having success with focus on negating his critical hit strategy and preventing him from using Dragon Dance. When doing solo, having one or more ally Pokémon with the ability Intimidate will help with his high attack stat.
Example Builds
Held Item:
Shell Bell
Ability:
Shell Armor
Tera Type: 
Nature:
Adamant
EVs:
4 HP 252 Atk 252 Def
Moves:
Iron DefenseTauntSwords DanceNight Slash
Held Item:
Shell Bell
Ability:
Anger Point
Tera Type:
Nature:
Impish
EVs:
252 HP 4 Atk 252 Def
Moves:
ProtectBreaking SwipeMud-SlapPower Trip
