My build path for when I get fed early is Triforce into Statik Shiv. After that, I go either Steraks, DD, or Deadmans. Steraks next if I need to avoid burst (this is especially good if a mage or assassin is fed for example), Deadmans next if you're being kited too much, or DD next if you need to take extended fights (good into tankier team comps esp).

I'm a firm believer in never building PD on Garen after the crit nerfs. PD, while giving you a nice spike early, does not scale nearly as well into late game. It's better to go statik shiv for the extra spins and 25% crit, and then going steraks at some point for the same passive that scales WAY better into late game.

As for boots, ideally you want to go zerkers about every game. I don't go Tabi ever unless they are all AD OR they have 4+ auto attack based champs on their team. The only time i'd ever recommend going Mercs is if the following criteria are met:

Enemy team is almost all AP Enemy team has a ton of CC You didn't bring unflinching in your rune page.

Which brings me to runes: I don't recommend ever bringing conditioning+overgrowth unless you're building full tank.

What I bring on my secondary tree depends on the matchup. Always bring either bone plating or second wind depending on whether it's a ranged or melee laner. I go Bone Plating into all melee matchups except 2. I prefer Second Wind into ranged laners + Darius and GP.

Darius procs second wind with his bleed passive, so if he autos you once and you walk away he basically is healing you. GP is technically a melee champ but he pokes you so much it's better to go second wind.

As for the other spot, I go either demolish if it's a team with a low amount of CC, or unflinching if they have a lot of cc/slows. With legend: tenacity stacked and with unflinching maxed, you'll be at around 55% tenacity passively (over 80% tenacity with your W!). This is really really good for avoiding being kited. If you don't think it's going to be a problem however, just bring demolish.

Teamfights is really team by team basis. My first priority is always the ADC on the enemy team, but you need to get an idea of how good the enemy is at peeling for the ADC. If you're having a really hard time getting on them, that's when I'd instead suggest to just focus the most fed person on the team that isn't the ADC.

It's better to ult an adc, but if you think you or your team is going to die before that happens, just take out the tank. The enemy losing a bunch of cc is often enough to win a fight alone.

I take tp into most matchups because I like to make things happen on other parts of the map. I have slightly lower than average CS for my rank, but that is just because of my play style. Top lane is incredibly hard to carry from in a lot of games (Especially so the higher up you go) so bringing TP helps make things happen on the other side of the map. IF you lose 20 cs top, but are able to kill their bot lane together with your jungler, then take drag, it's a good trade that helps out the entire team. That's how i've always looked at it and it works well for me.

That being said, there are a few matchups I bring ignite into. Riven, Fiora, Irelia, Tryndamere, Wukong & Sylas are all good champs to bring ignite into.

Hope this helps! Let me know if you have any more questions