Garens build in this guide is semi focused on the combination of a few of his items with his own abilities,
First Item Combo: the Farmer
Wriggles/Madreds razors, Avarice Blade: This combo is designed to increase the farming ability of your (E) since your very early game item builds aren't massively powerful until you can afford INF EDGE

Second Item Combo: The Defender
Wriggles, Mercury Treads: The Added minor Armor and MR boost early with these items can make Garen a decent tank early game

Third Item Combo: The Critical
Atmas Impaler, Phantom Dancer, Infinity Edge: These three items pop your crit chance to 75% Meaning that youll usually hit criticals, Including the Crit Damage Boost from IE, and The AS/MS boost from Phantom, as well as the massive base damage boost from atmas and Phantom, these three items become youre core damage dealers, REMEMBER (E) can Crit

Final Item Combo: Damage for Health
Atmas Impaler, Warmogs Armor: Atmas takes 1.5% of your health as bonus damage, Warmog basicly doubles your passive and sustains it in combat, as well as adding 1000 more health (that means an extra 15 damage) to youre already bruisery build. Even if your massively low on health, go farm some jungle to use wriggles, and youre around 18 health regen per second to make better use of your time than Recalling.

Combo 1: The Spirit of Defense
Spirat Visage, Ninja Tabi: These two items will put you miles ahead of enemy chamos in terms of defense, and its worth noting that the passive 20% healing boost from Visage also works for your own passive

Combo 2: The Spirit of Healing
Spirit Visage, Ravenous Hydra, Warmogs Armor: Visage 20% also applies to Warmogs Regen, and Hydras Life Steal as well as the AOE from Hydra, spirit also boost your health a bit giving warmogs and your passive a bit more juice to heal.

Combo 3: Health for Damage
Atmas Impaler, Randuins Omen, Ravenous Hydra, Warmogs Armor, Spirit Visage: Randuin is 500+hp, Spirit is 200+hp and Warmog is 1000+hp Totaling 1700+ 2180(youre lvl18 base health) + 370 or more (the extra 1.5% from the quint, and the masteries) Leaving you a grand total of 4250 Hp
Atmos Takes 1.5% of 4250 as damage (63)
Warmogs Heals for 1.5% per 5 seconds (63)
Passive Heals for .5 Per 5 seconds (21)
Garens Base Regen = (21)
Spirit Gives 20% boost to all constant healing = 20
You heal over 140 HP every 5 seconds