Ok, where to start? I never wanted to look at your guide until now because the title blew it off. Garen is NOT a tank, he's a tanky fighter, similar to things like Olaf, Jax, Sion, Blitzcrank, Jarvan, Nasus, or Singed. If these guys are tanks to you, I'll eat my computer. Sure, some of them(Jarvan, Blitzcrank) can be played as tanks, but that's because they have the CC necessary to pull it off, all Garen has is a puny, one target silence(good luck tanking with that). All of the things they have in common is the fact that they can kill people, like carries and assassins while still being sturdy enough to survive many nasty encounters, in which they take a good beating, similar to tanks. What differentiates them is the kind of damage they mainly dish out, guys like Garen and Olaf deal physical damage, Singed or Blitzcrank focus mainly on magic damage, while Jax is a hybrid. There are others I haven't mentioned like Riven, Wukong or Shyvana. Are they tanks to you? I don't think so. Garen is most similar to these guys. If they're neither tanks, nor AD carries what are they, I bet you wouldn't build them glass-cannons like Tryndamere, would you? They are OFF-TANKS and so is Garen.

Anyhow, skiping ahead the ideea on which your guide is built is completely wrong. I'll tell you why, because tank Garen sucks, he's impossible to kill, but he's completely harmless and everyone on the enemy team ignores him and goes for the real threats. Even worse he has no form of CC to stop them from doing so. This means that the ideas that u start your guide on are extremely wrong.

Secondly, why would you have a game philosophy in which your main goal is NOT to have a positive score, but to die in the place of your companions. Even as a real tank, u should expect the best out of the game, sure dying is a tank's job many times and he does it for the team, but real tanks are so tough that even though they get focused, they never die, they still stand after the entire enemy team has been exterminated(or his own). Building a tank that ISN'T indestructible doesn't make sense. The only thing notable in your guide is the tanky DPS build, but even there u fail. The best off-tank build for Garen is Frozen Mallet, Boots of Swiftness, Infinity Edge, Atma's Impaler, Phantom Dancer and either Banshee's Vail or Sunfire Cape, depending on the situation. This is a build that gives tons of health(almost 3.5k), a sick amount of AD(over 300), both armor and MR, well over 100, an attack speed of 1.3, a movement speed that will make you catch everything that moves(except maybe a Master Yi), and an incredible critical hit chance of 75%, comparable to Tryndamere(this will make it worth for Garen even to auto-attack). What more could you ask for? This is the way Garen is MEANT to be played, not as a silly punching bag, but as the terror of the battlefield, deadly and incredibly hard to kill. If I was a bad person I'd give this guide a thumb down, but since I don't do that kind of things, I'll just settle with this constructive criticism. Garen is, by far, the worst tank I have ever seen in this game, hell even mages like Vladimir or Morgana would make better tanks than him. Building him this way symbolizes everything that's wrong with the LoL community, making a guide about it is even worse( the fact that people actually like it is mind-boggling), where the hell did you people get the ideea that Garen is a tank? Riot never intended him that way, their idea was of a very hard to kill fighter, that can exterminate all opposition up close and dangerous and live to tell the tale(Phreak even said about the same thing in the champion spotlight, the guy is not only an admin, but he's a freaking godlike LoL player, he doesn't use Garen as a tank, why would you?), his description in the sheet is melee/ fighter, doesn't say "tank" anywhere I simply don't understand this, like I said, playing Garen as a tank is just as if you'd play Riven, Shyvana or Wukong that way, it's just wrong and it's a waste of potential for one of the best damn killers in the game. ******* it, if you relaly want to tank so bad, why the hell would you pick Garen for that? Why not Amumu, Malphite, Alistar or Rammus, why would you insist for your team to go in late-game team fights practically in a 4 vs 5 situation, playing tank-Garen is just the same as going afk, only use for him would be stealing some kills with Demacian Justice, those guys that manage to get away with low health.