Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
This is by no means the BEST Garen build, but it has shown to be very useful in my experience of playing him. The last game i played with him i went 41/7/13 and if u practice a few times and learn how to play him, you SHOULD be able to do very well with this build.
Quickly Grab a Doran's shield and run to your lane. Garen is very good in an early game gank; so trying an early game gank with a lanemate could be very useful. If you would rather play it safe, wait for minions to spawn and farm defensively until you get your ultimate.
After getting Boots of Swiftness and an avarice blade, start to set up ganks in other lanes. With your high damage output from judgment, and the silence from decisive strike, followed by Demacian Justice, you should be able to rip through squishy champions and most tanks by that time.
Start grouping in the mid lane with your team and push towers and their inhibitor.WARNING: DO NOT PUSH UNTIL ALL 5 OF YOU ARE IN MID! There have been countless times that I started pushing with only 3 or 4 of us and we all got destroyed because they countered our push with 5 people. After getting the first inhibitor down, push the two sidelanes, and then target the enemy Nexus.
I hope this guide is as useful for you as it is for me. Feel free to comment if you feel the guide needs any changes.