The Goliath is big, slow, and extremely powerful. He has a lot of armor and health, which takes a while to get through. Hit him with Val or Lazarus’ Sniper Rifle to create weak spots for the other Hunters to aim for.
You can dodge Goliath’s Rock Throw and Leap Smash, but you must be ready for them. Keep Jet Pack fuel in reserve in case you need to make a quick dodge. If possible, fight from a higher point or behind some cover.
Stay in the open against Goliath. If he pins you in a cave or a corner, his melee attacks and Fire Breath are deadly, and it is tougher for a teammate to get to you when you need a heal or shield.
Keep some distance between the Hunters. All of Goliath’s abilities can hit multiple targets. If everyone is in a tight pack, you can all take serious damage in little time. Watch out for Goliath’s Charge ability, which can clear out your group fairly easily. Dodge out of the way and use this opportunity, as Goliath passes by, to hit it with a big attack.
He is the least stealthy of the three Monsters, though a Goliath that hides behind a building or brush can still get a Pounce attack on an unsuspecting Hunter.