Like I said earlier, Pantheon's kit allows him to really deal a lot of damage, even if he doesn't build any attack power at all. This falls off late game, so you have a choice - you can either start building damage late game and go for a bruiser build, or go full tank nd hope for a strong enough early game with him that you can carry into the mid game and win early.
Here's some tips:
- When you attack, don't underestimate your physical attack. Alongside spamming your Spear Shot, you should attempt to land physical attacks as often as possible. Try to get behind them so you can land as many hits as possible as you chase.
- Always use your Heartseeker Strike to finish. It really has a longer range than you think! You don't want to use your Heartseeker Strike early on because it requires that you stay planted on the spot, and it will give the target a huge opportunity to get away. Plus, if you move, it cancels, and you have to wait for cooldown again. This effect is worsened when your opponents begin to build tenacity. Yet another reason to save for last is because it will crit when they are at low HPs. As your attack power scales up this will become more and more effective.
- Lay off of your Heartseeker Strike in the jungle. You can jungle almost as fast with Spear Shot alone and it's much less mana spammy, giving you more mana to use in ganking and helping your teammates defend lanes.
- Constantly search the map for opportunities to make use of Grand Skyfall. Don't jump the gun though. You want to make it worth it. It stinks when you have to use it to defend someone's lane when they die, but, that's just the way it is - it's a team game.
- When you use Grand Skyfall you can also cast Aegis of Zeonia on a target before you even land, ensuring that you will leap the moment you land, as long as you're in range.
- Use your Grand Skyfall -> Aegis of Zeonia combo to stomp weak champions hugging their towers. Make sure you signal your team and they know what you're about to do or they won't know to push the tower.
- A Flash -> Aegis of Zeonia can stop fleeing champions in their tracks and secure a kill for you or your team.
- When ganking don't always initiate with Aegis of Zeonia. You are more effective if stay behind them and throw your spear and force them into a situation where they have to run either towards you, or the champion in their lane. If they choose you, then engage at melee range and burn Aegis of Zeonia when they try to Flash. If they choose the lane champion they will give up a lot of position, and you should immediately use Aegis of Zeonia to protect your teammate.
- Your role in team fights late game is to disrupt and protect your teammates, while focusing down any squishy champions and dealing as much AoE as you can. If you are going for a bruiser build, absolutely kite and don't all in every teamfight. A bruiser should always play it very close to a overcommit - this will draw the attention of enemy champions who will sink some of their damage and cooldowns on you, while you leave the chance to kill you just slightly out of their grasp. While you are in the hot zone is when you let loose with as much damage as you can before you get out to safety. This sort of off tanking strategy makes maximum use of your abilities - both to deal damage and absorb it.
- A good combo which will absolutely _STEAMROLL_ squishy champions before their stun even wears off is Grand Skyfall -> Aegis of Zeonia -> Physical Attack -> Spear Shot -> Physical Attack -> Heartseeker Strike.
Thanks for reading. I'll try to update as I get more knowledge!