Hi this is Aeromancer here, this is my first guide here but I wanted to show people how I like to play Garen.

Pros

[*] Farms like crazy [*] good early game [*] Shreds ADC's and most AP's [*] Can run right through most CC

Cons [*] Easily Poked [*] No Harass [*] little CC [*] not the best late game

- usually take this along with

However.....
- Is a great spell vs really annoying mobile high AS champs, you pop Exhaust on them and chase them down! Could either replace Flash or Ignite, But I would suggest replacing ignite because.... Play Video to put it in Raka terms.
No but seriously, you already have a finisher so another, ignite, is just overkill

To me these marks are pretty straight forward but ill explain them anyway.
Greater mark of armor penetration Greater Mark of armor penetration- To cut through your opponents armor better, but it can be replaced with Greater mark of attack damage
Seals are pretty straight forward, most AD champs get these greater seal of armor
Same with the glyphs, I believe they are pretty commonly used, greater glyph of magic resist
The Quints however are the opposite of marks, in a way. I usually get greater quintessence of attack damage
But greater quintessence of armor penetration greater quintessence of armor penetration- works well too, it really depends on who you are fighting.

This guide is a work in progress, I will be adding alot more, but for now this is what I have. if you have any comments or concerns please feel free to comment and/or rate. Thanks all for your cooperation!