Not Updated For Current Season
I begin game with a Meki Pendant, Health & Mana Pot, and immediately build into the Chalice of Harmony my first visit back to shop.
Second Item is always movement because you won't get many kills being slow. Mercury's Treads is the best in game due to how many roots/stuns exist between the champions. This is especially true for a 5v5 match. If you are playing a team with minimal CC then the Berserker's Greaves or Boots of Swiftness are recommended.
For the Rest of the Game the Itemization follows the list. You normally won't finish the Trinity Force by the time the game ends.
Haste gets more hits with your Righteous Fury. Armor Pen is obvious and necessary. The Health is for early game mainly and can be substituted for either AP Seals /plvl or dodge seals.
Early Game ->
get the gank if you can, but you wont be effective until level 3 when you should have your Righteous Fury Available. Don't blow it unless you are keeping them off the tower and or going for the kill because you need chalice to replenish the mana or you will be oom for the entire early game. Chalice is a good early game grab. I normally return around 1200 gp and or lvl 6/7ish when the tower looks good. The chalice will let you sit at the tower and literally farm using your Righteous Fury and Divine Blessing. Reckoning idiots that get too close, let the tower do a hit or so while you blow Righeous Fury to take him down.
Make good use of the Divine Blessing's Speed increase upon use. This will help get you the kills.
Tower Diving like a pro with the Intervention will seal a lot of kills early game/mid.
Mid Game ->
Farm for items, and get some good team fights in. You Can solo if you are fed a ton, but otherwise I would advise against trying to gank someone until you have at least Guinsoo's and 2 BF Swords. You do Great Damage, but are still very squishy mid game.
End Game ->
If you got enough Early and Mid Game Kills you should be stacked for with an Infinite Edge and can dominate most team fights with your AoE. Using Key Interventions will keep tank or major dps units up (including yourself).
I normally pick up two B.F. Swords before I turn either into their final form for more mid game damage.
use your ghost for getting kills, and fleeing similarly to your Divine Blessing. Flash could be exchanged but Ghost is > imo.
Any Questions please Comment, this is my first build posted and i do pretty well with it. Last game 16/6/18 Victory.