This is generally what I get when I play Athena support. Start out with Sentienals embrace, keep in mind that you want to go into Gauntlet of Thebes but only get the tier one item, then go back once you have enough gold and get full boots and THEN build gauntlet of thebes.
I mainly get chronos pendant after just for some more cooldown and a bit of power and it works out pretty well. After my whole build is done I sell my boots and get void stone or another item which is really up to you, you could always replace mail of renewal with something else in its place but I generally use that. Void stone could come early or later, depending on how your game is going or depending on how you're feeling about what you want to build.
Sentinel's Embrace
AURA - You gain 8 GP5 if you have the lowest gold on your team. Evenly split 60 Physical and Magical Protection among all allied gods within 55 units and yourself. If you are alone you only gain 30 Physical and Magical Protections.
Emerald Talisman
PASSIVE - Regenerates 0.2% of your max. Health every second.
Shoes of Focus
S8 Meditation Cloak
Using this item restores 75 Health + 12 Health per level and 30% Mana to all Allied gods within 35 units. Cooldown - 120s.
Chalice of Mana
This consumable heals 150 Mana over 25 seconds per use. Comes with 3 uses that are refilled if you enter the Fountain, sells for 0 gold
You could either get Magic shell or Meditation Cloak for your relic. I generally use Med cloak because my Carry runs out of mana fast and it's also a good way to keep them alive and have them escape. I usually get Mana chalice cause you'll have an extra 300 gold left over at the beginning of the game and I generally use a lot of mana at the start.
Sentinel's Embrace
AURA - You gain 8 GP5 if you have the lowest gold on your team. Evenly split 60 Physical and Magical Protection among all allied gods within 55 units and yourself. If you are alone you only gain 30 Physical and Magical Protections.
Gauntlet of Thebes
PASSIVE - Assists on a minion give 1 Stack and God kills and assists give 5 Stacks. Stacks provide 1 Physical and Magical Protection. At 45 Stacks this item evolves, providing an Aura of 10 Physical Protection and 10 Magical Protection.
Chronos' Pendant
PASSIVE - Every 10s the Pendant activates, subtracting 1s from all of your abilities currently on Cooldown. The initial countdown will not start until you leave the fountain.
Mail of Renewal (old)
PASSIVE - You gain 15% of your maximum Health and Mana over the next 3 seconds when you get a kill or assist against an enemy god or Objective.
Breastplate of Valor
Void Doumaru
AURA - Enemy gods within 55 units have their Magical Protection reduced by 10%.
Once your build is done but with boots still included, you should buy Elixer of speed whenever you have enough gold for it, and then when you save up around 1500 gold again, sell your boots and get an item to replace them. Get Heavenly Wings as your second relic.
Here it's mainly up o you, but always get Shield wall first, then confound, and then preemptive strike.