I disliked because some of this info isn't even updated. Gave ample time for stuff to be updated when I first originally posted as I would of liked this to be my go-to guide for Garen, and I am sadly disappointed at how this guide is neglected in some portions. (Will the masteries pic every be updated? We'll never know!)

Thanks! Great guide btw!

Haven't faced Fiora since pre-rework I think. Pretty much though, even pre-work Garen with all his early game damage couldn't match Fiora. However all her damage is besides her parry which you shouldn't get hit by is physical. So just build armor and start laughing at her as she breaks her flimsy rapier on your manly man breast plate. Never Q her while her Parry is up.
Garen has the edge of having a magic damage nuke that most people forget is magic damage, so as they stack armor against you they get caught off guard.

Just lost a lane to Fiora. Do you have any advice how to play against her?

I haven't faced Zed much and since he's not the easiest guy to play well I can't be sure if the few I fought were any good. I also haven't laned against Xin since Season 2 so not sure how much more he whoops you early on with the penetration changes.
My go to against pretty much all difficult matchups is to simply build resistances to mitigate their damage so I can just farm or finally out trade them.
Against Xin if you play safe early on you should be able to bulk up and be able to beat him at 6 or force him back since your ultimate is better suited for dueling. Zed will keep his distance though and just harass so just wave clear and look for a gank.

Its about time to update your masteries pic, man :P Season 2 is WAY over

Great guide, helped me out a LOT. I've been carrying games where we had a terrible start and I'm talking like 0-10...but...I have a problem with these 3 champs:
Xin zhao and zed(the hard ones) and lee sin(depends on the player).
Xin zhao just owns me with his 3 talon strikes, and zed just keeps on harassing whenever I come close to hitting a minion.
And as for lee, I can dodge his range thingy but he still can beat me if he's good.
Also, what do you think of the latest garen nerfs?

I've rarely started with Dorian's Shield during Season 3 to be honest. Potion Master Garen (with wards) is too strong, or even starting with a flask.
Each start has it's pros and cons. Starting with potions and wards lets you stay in lane the longest normally, but if you get ganked or killed early it's a total waste of an investment. Dorian's Shield start gives you regen and tankiness to stay in lane, but a jungle gank or highly aggressive opponent can force you out of lane also, but at least your Dorian's Shield investment stays there until you sell it.

I never go boots, unless I'm fighting Kayle, where I need to speed to catch her after I Q out of her slow.

Wards save you from ganks. Dorans shield or boots+pots all depends on your play style.

Should i start with a Doran's Shield or pots + ward? I've always started with Doran's Shield and been successful. But a friend of mine said pots + ward was the way to go. Can you clarify?