Few Opening Words:

So i see you want to play few games on Pantheon, i'll give you build what will give you the pleasure of win

You can do some Experiments on that build you don;t need to exactly follow what i've done but that;s good way to get high stats.

Theme Of Build

I've decided to make Panth on AD/AS with some Life Steal, as you surely know his abilities have + from your attack damage so you wil be able to do a massive damage to your opponents after buying some of items showed up there

Runes:

I have decided to take:
Marks of Desolation (giving you some Armor Penetration)
Seals of Devasion (some dodge chance)
Glyphs of Clarity (mana regen raising per lvl)
Quintessences of Desolation (Some armor penetration too)

Too choose this runes i've read this guide :
Rune Tips what secondary and Primmarey means

Masteries:

Classic. Masteries are 21/0/9 Offence and Utility
Offence will give you some more Armor Penetration, utility will reduce your time spend dead and will give you faster lvling.
Nothing else to say

Spells:

So here you will read about using your spells in ganks

Good Spells Are:

- Basically that will give you an chance to kill people 1 vs 1, Jump in with your ulti hit them with shield use
Heartseeker Strike and then exhaust.
- just like in all other champs when you will jump on with ulti, you can use ignite well and exhaust your enemy then instantly throw ignite use exhause heartseeker etc. that will be pretty easy kill
- I like to youse this spell mostly, it gives me chance to chase the ennemy, when i throw exhaust on him that will give me chance to chase him even when exhaust expires ...
- Instant Chase enemy. Can be use also for good gank Flash->Shield Hit->Heartseeker Strike->Exhaust->Spear->Chase

The rest of spells i consider as bad.

Recommended:

- Attack Damage (powering your abilities) and Life Steal (really important in Mid and Late game)
Critical Strike Chance (you will need this to use your Life Steal) Attack Speed (That's pretty important too to use your Life Steal) and Movement Speed (15 % is nice ammount consider that you will have 2 Phantoms stacked togheter with 30 % Movement Speed)
- Attack Damage (As i told it already that will power you summoner abilities) Critical Strike(Now it will be stacked to 50 % Life Steal will be Huge)
250 % of your critical damage, that's pretty important cause you will need uber Crits.
- If you will play against strong Tanks try to buy also this instead of an other item.

All stackable items on such Champion as Pantheon are noobish don't use them, cause if you will not be able to stack them up you will be a weakest Summoner with small ammount of Attack Damage Attack Speed etc you will only waste your money

So here i will explain some basics of Early Game on Pantheon.
and also some Mid and Late game tactics.

Early Game (1-8lvl)

Basically Early game on Pantheon is really hard, you will need to handle to 6 lvl.
First of all when you wil have 3rd lvl your ganking abilities will instantly raise up (You have stun now !)
When someone will have really low HP just go to him with Shield Hit (i don't remember the Ability name so don't bother me with that)
and then simply youse the rest of your abilities to finish him (possibly if you have exhaust it will be alot easier to do it.)
As soon as you will reach 6lvl jump in with ulti for ganks, but care about the accuracy of your ulti you need to predict what will happen (that you will learn when you will play some time with this champion)

Mid Game (9-13)

At this stage you should become an OP champion
When you will have The Bloodthirster your abilities will strong kick of damage. That will let you eat opponents.
But be aware of ganks on you you almost don;t have health.

Late Game (14-18lvl)

That stage is the most important so i marked it on red color
Tactic is pretty simple, when you see that there is going to be Team Fight, tell all your tanks to rush in to the circle and jump on the enemies head (that combo is supper effective when Nunu uses his Absolute Zero skill.
You will still have pretty lame ammount of health. So still be aware off ganks on you you will be easy target so predict future check map, and use some Wards.

So you will need to choose what death will have King Leonidas, if he will be a heroic Summoner and will he defeat Persians ? Or he will be a coward what will run from Barbarians
It's all up to you now .
Good Luck on the Highway to Hell