I'll start with the finishing items, for those that are only looking for a build guide rather than a play-through guide.
I know. Sorry I can't tell you what exactly to build, but here are some suggestions, along with the situations that may require their use.

You've bought the Avarice Blade and don't know what to do with it, unless you have a substantial gold lead, I recommend you build it into Statikk Shiv, it also procs with your Flay's passive and your Trinity Force's Spellblade passive.

This item is bugged right now, it currently slows Thresh's autoattack speed to the same speed as the additional projectiles. Buy it maybe when it's been patched.

You have a better score than the enemy team, but you end up losing teamfights:

Second Life (5 min cooldown (CD))
Protection from APC and Magic Resist/Damage

Too much armor or hp on enemy team?

+200 HP and Armor Shred
Lifesteal and % HP damage, use in longer drawn-out fights with Tanks
Armor Penetration

Dominating the enemy team?

For 1v1 duels when split pushing, gives better burst damage.
For 1v1 Hunting, active is good for chasing/escaping overextending noobs on the other team.
Once again, for hunting down those overextending noobs, good slow and health boost.

I was asked this question, so here it is:

After using any skill, your next autoattack will deal damage from four sources, if you include Blade of the Ruined King:
1) Auto Attack Damage (Can Crit)
2) Flay Passive Damage (Cannot Crit)
3) Trinity Force's Spellblade (Cannot Crit)
4) Blade of the Ruined King's passive (Cannot Crit)

For simplicity's sake, we'll say Thresh is Level 18 with no masteries/runes and has 86 Base Attack Damage, along with the 30 Attack Damage from Trinity Force and 25 Attack Damage from Blade of the Ruined King and an Infinity Edge with 70 Attack Damage for a total of 211 Attack Damage. Let's say he has 50 souls.


Scenario #1 (BotRK rather than BT)

So our damage is calculated like so:
1) (Critical Strike) 250% x 211 Attack Damage = 527.5 Physical Attack Damage +
2) (No Critical) 50 Souls + 200% (211 Attack Damage) = 472 Magic Attack Damage +
3) (No Critical) 200% x 211 Attack Damage = 422 Physical Attack Damage +
4) (No Critical) 5% x (Enemy Health : 3000HP) = 150 Physical Attack Damage

For a total of ~1100 Physical Attack Damage and 472 Magic Damage
or 1572 Damage in total. It sounds about right, I've seen some ADC/APC's health bars go from 90% to 15% as a result of that one autoattack.


However if we substitute a Bloodthirster in, instead of a Blade of the Ruined King, we get:
Physical Attack Damage :
Initial 211
-25 (Taking out Blade of the Ruined King)
+100 (Adding Bloodthirster with full stacks)
Final 286


Scenario #2 (BT rather than BotRK)

So we have 286 AD and only three sources of damage on our first autoattack:
1) (Critical Strike) 250% x 286 Attack Damage = 715 Physical Attack Damage +
2) (No Critical) 50 Souls + 200% (286 Attack Damage) = 572 Magic Attack Damage +
3) (No Critical) 200% x 211 Attack Damage = 422 Physical Attack Damage

For a total of ~1137 Physical Damage and 572 Magic Attack Damage, or a total of
1709 Damage.


Of course I didn't include Armor/Magic Penetration or Armor/Magic Resist, but they are both proportional regardless of whether you have the Bloodthirster build or the Blade of the Ruined King build. For example if resistances decreased the damage in Scenario #1 by 25%, it would still reduce the damage Scenario #2 by 25%, and it would still be higher (the damage) in Scenario #2. Anyways, the enemies you should be focusing, should hardly have any armor or magic resist at all. (lol)

In Scenario #1 with the Blade of the Ruined King, I gave the enemy 3000HP for the passive damage to calculate, however, I'm sure most ADCs don't even have this much HP, so it would do even less damage.

I guess that's my reasoning:

- Trinity Force
- Bloodthirster
- Infinity Edge

= 1137 Physical Damage
= 572 Magic Damage
= 1709 Damage


- Trinity Force
- Blade of the Ruined King at 3000 HP
- Infinity Edge

= 1100 Physical Damage
= 472 Magic Damage
= 1572 Damage

So with a 3000HP Opponent Bloodthirster > Blade of the Ruined King
Blade of the Ruined King Scales with HP, so lower HP = lower damage.

Of course this is only in terms of the first hit, the Blade of the Ruined King is better over time as it has it's +40% Attack Speed as well as it's passive, however I'm focusing on trying to kill the enemy as fast as possible, so I made my guide with the intention of a DPS/Burst Hybrid Thresh. This setup usually kills the enemy squishies in 2 hits, if feel if it takes longer than that, then I may as well end up dead as the enemy team reinforces their teammate.

Thanks for reading!

http://leagueoflegends.wikia.com/wiki/Thresh/Ability_Details
http://leagueoflegends.wikia.com/wiki/Trinity_Force
http://leagueoflegends.wikia.com/wiki/Blade_of_the_Ruined_King

Although I play ranked, runes only provide a slight advantage in bottom lane. You can go with whatever runes you want. For example, my standard ADC build is:

9x Greater Seal of Scaling Armor
Armor / Level
+1.35 Armor (In total, +24.3 Armor at Level 18)

9x Greater Glyph of Magic Resist
Magic Resist / Level
+1.34 Magic Resist (In total, +24.04 Magic Resist at Level 18)

9x Greater Mark of Attack Damage
+0.95 Attack Damage (In total, +8.5 Attack Damage at Level 1)

3x Greater Quintessence of Armor Penetration Greater Quintessence of Armor Penetration
+2.56 Armor Penetration (In total, +7.68 Armor Penetration at Level 1)

I'm sure most players at least use the Seals for Armor and Glyphs for Magic Resist as an ADC, I recommend you do that as well. As for the Marks and Quintessences, you can determine what is necessary.

The pure attack speed rune page is the one I often use, it works quite well for farming and late game fights.
This setup gives a +38% Attack Speed boost. You'll notice the difference even at Level 1. Usually you'll end up with 0.89 Attacks/Second at the beginning of the game, while your ADC (if you have another one) starts with around ~0.7 Attacks/Second.

Pros

Cons

---

+ Flay provides passive damage that helps poke in lane + Thresh can peel for himself (CC), using Death Sentence, Flay and The Box + Dark Passage is useful for saving teammates and bringing in jungler ganks quickly +During late game, The Box can save you from an unwanted engage +Passive Damnation gives bonus armor and ability power in lane

-Second shortest attack range -Susceptible to CC -Cannot initiate in 5v5 teamfight since Thresh is taking on an ADC role -Low health and no sustain early game

This chain shows the priority at which you should level your skills, with the left-most skill being the most important. So we would level The Box over Flay and Dark Passage over Death Sentence. However it's up to you what to get at level 1, Flay is there for standard laning, but if you're going for an invade you might want Death Sentence for that first blood, or Flay for a level 1 team fight.


In bot lane, The Box hails both as a source of damage as well as crowd control, it helps secure that kill. However, be aware that champions can Flash over your walls to avoid the damage and 99% slow. We max this as soon as possible because each level grants 150 more damage, which is quite valuable in a squishy bot lane.

We max this skill second because it provides massive damage for your poke, this passive damage combined with your Sheen will allow you to win trades easily, so long as you dodge skill shots (e.g. Ezreal's Mystic Shot).

Make sure you check your minimap once in a while, just in case your jungler is being chased down by their mid-lane and jungler, or if your mid-laner is coming bot for a gank. Dark Passage is a useful method of travel that allows movement through walls, saving your teammates and creating excellent opportunities for jungle ganks ( Jarvan IV's Dark Passage-> Demacian Standard-> Dragon Strike-> Cataclysm combo , or Lee Sin's Dark Passage-> Sonic Wave-> Resonating Strike-> Tempest-> Dragon's Rage-> Cripple combo). Once again, try and keep track of your opponent's Flash cooldowns and usage. Leveling this skill up provides a stronger shield, which could prevent your laning partner, or yourself, from giving up a kill.

This skill is not useful because of it's damage, but rather it's utility, so early game the most you would need is one level. The hook provides a 1.5 second stun, the second activation removes the stun, but allows you to travel towards your target, whom is hopefully at low health, and finish them with a Sheen proc. In a 2v2 bottom lane fight, when your laning opponents have lower health, this works a good initiating skill. Be careful, this is blocked by spell shields (e.g. Sivir's Spell Shield, Nocturne's Shroud of Darkness)

I'll start with our most simple combo, but before trying this out make sure you burn the enemy's Flash first.

->Tug twice towards support-> Dash towards victim-> The Box-> Flay enemy into box edges.

This skill stuns! Capitalize on this fact, it also brings you towards your enemy. It can disrupt channels. It's a skill shot, and a slow one too, make sure you aim AHEAD or BEHIND.


As I've been mentioning the uses of all these skills throughout the guide, the shield can save your teammates and bring them along for a gank.







Here is a video that shows how to execute this combo:

Nowadays the support meta isn't really there. You'll see a wide variety of supports ranging from LeBlanc, Dr. Mundo and Annie. Personally I feel that Taric would be the ideal support for Thresh with a stun and a heal. I feel that in Season 4, the most important thing about bottom lane is sustainability. For example, when laning against an Ezreal or Annie , usually you end up getting poked. Having a support that can heal you (e.g. Imbue , Astral Blessing ) or provide mana (i.e. Infuse) allows you to lane without fearing a gank while you're at 20% HP, or having to back after losing a trade.

Pro Tip:
Always keep a minimum of two wards on hand, if you're on the Blue team, use it to only ward the "Tri-Bush", and possibly for the bottom bushes, if you fear there are champions waiting to kill you (e.g. Lee Sin , Blitzcrank , Thresh (In Normal Game), Vi , Sejuani , Fiddlesticks , Leona , etc).

If you are on the Purple team, use one ward on the "River" bush, and once again, the other in a bottom bush if you fear an impeding chain/grab/stun of DOOM.

Usually, I end up with an ADC in bottom lane, such as Lucian or Vayne. If you have the attack speed runes, you'll have the ability to take all of the farm. In Normal Games, there are usually no complaints, but I find that there are many more ragers in the community nowadays, so if you would like to save yourself some grief, ignore them in chat.

Remember, you are ideally saving up for a Sheen, on your first back!

Ok. This BBcode thing tires the **** out of me. I don't want to have to insert every champion name into this chapter. So I'll sum this up.




First of all, as Thresh ADC, what you want is:

A laning partner that can operate as:
-Bait (Person *****ing about wanting to be ADC)
-A Crowd Control Champion (e.g. Leona)
or
-A Healer, or sustainable champ (e.g. Sona)

Who you don't want as a laning opponent:

-Someone with spell shield (e.g. Sivir)
-A support with heavy damage (e.g. LeBlanc)
-A support with tons of CC (e.g. Leona)

Of course all of this isn't possible, my belief is that your farming skills, skill shots and psychological understanding of League are the most important factors that play a role in laning phase. For example, when to capitalize on your opponent (i.e. poke them when they are going to last-hit) or being able to predict enemy movement patterns (i.e. MID MIA means: Enemy mid-laner is going top/bot for a gank, blue buff, or helping their jungler steal our blue buff etc).

These skills are not attributed to certain champions, they come from experience playing League as well as being able to use a brain.




Anyways, we covered our ideal supports already, Taric, Sona, Soraka etc. However normal ADCs as your laning partners (e.g. especially Jinx) provide good support as well. For example, in a 2v2 fight bot lane, they won't be able to shut down both of you damage-dealers, and usually it ends up a 2 for 1 trade, or even better a 2 for 0 trade. Jinx is especially a good laning partner because her Zap!, Flame Chompers! and Super Mega Death Rocket!, do damage or stun/slow, keeping enemies off you and allowing you to win trades. We already mentioned Taric, but Leona is also an outstanding support as well, her Sunlight passive helps your damage even more so.

Remember to ward bushes for junglers! And to dodge hooks etc!




On another note, sometimes enemy lanes are hard to fight against (i.e. Graves and Taric) because of their overwhelming lifesteal, heal and high HP, as well as your few opportunities to poke. In these situations you need to freeze lane by your turret, and ask politely for ganks. Patience is a attribute all pro players have, it wouldn't hurt now to practice being patient.

Anyways in this situation FREEZE lane.




The next situation:
You have an enemy lane with a crazy damage dealing ADC (i.e. Draven with his Spinning Axe) and a healer (e.g. Sona or Soraka) with low HP. Once again, patience, you have to poke, and wait until the support runs out of mana, poke a bit more, and then engage before the double kill. Oh yeah, focus Draven please, if you believe in your skills, you can Flash to dodge Sona's Crescendo.



Another painful situation:
You have an enemy lane with Sivir and her annoying Spell Shield.

Her cooldowns from level 1-5 respectively are:
Cooldown: 22 / 19 / 16 / 13 / 10 seconds.

Your cooldowns from level 1-5 respectively are:
Cooldown: 20 / 18 / 16 / 14 / 12 seconds.

This means if you do hit her, all you'll be doing is providing mana.

And even when you do manage to hit her with your hook, she has A FREAKING Leona to SAVE HER and KICK YO ***.

My suggestion is DO NOT ENGAGE. Play the Graves/ Taric strategy, and freeze lane near your turret, DODGE her Boomerang Blade while she loses mana from spamming it and wait for a gank. I suggest you only engage if you have an ADC as a laning partner, and while Leona and Sivir bash your ADC, you can pull off your combo (Standard Thresh Combo)

I think I've covered the most difficult lanes. For the most part, anything goes!

So throughout the game, there should at least be one thing on your mind.

Farm. Or CS.Or just GOLD in general.

In order to get the items you want and finish your build, you should be farming lanes, and if they are pushed, go jungle. Exp and Gold are both important factors that determine team fights. Gold more so late game, EXP more so early game (especially pre-6).

Once you have won lane, it is up to you whether or not to farm champions in the bottom lane, or take the turret. Your lane will naturally push out as there is no enemy turret to thin out your creep waves.

At this point you can roam, and gank top or mid lane, and push those turrets as well. Typically the downing of one turret means the end of laning phase, still call MIAs though ("Missing in Action"). This is pretty much mid-game. Please help out your teammates and ward objectives such as the Ancient Golem , Lizard Elder and Dragon , later Baron Nashor . Most of your kills during mid-game should be derived from the fact that you warded the area.

Wards win games. The shift from mid-game to late-game occurs when most of the outer turrets are down, and when teams group. This is why warding is vital, to prevent teammates dying from overextension (traveling too far alone and farming), running into their team, or facechecking a bush they've camped.

Always plan objectives with your team. These tactics take place in every game, I don't think every guide you read should have to cover this, but sometimes I ask myself "What the hell do I do now?" after I've downed the first turret. So here it is.

Good luck!

Well this is the page I use to cover my ***, in case I've forgotten any important points.

For example:
TEAM COMPOSITION:
Every team only works if their champions are selected with the intention of creating a great team composition. That means, Thresh ADC will ONLY work, if you have teammates that are tankier than him and do NOT require him to INITIATE.

Late game, Thresh will become a focus if your skills has proven themselves, therefore it is not wise to ask your Thresh ADC to initiate a teamfight using his Death Sentence and The Box.

Please don't make a team composition like so:
- Kha'Zix Top
- Rengar Jungle
- LeBlanc Mid
- Soraka Support
- Thresh ADC

You don't have any tanks! You won't believe how often this happens in ranked play...QQ

This is twice as bad when the other team looks like:
- Renekton Top
- Vi Jungle
- Brand Mid
- Annie Support
- Jinx ADC

An Ideal Team composition actually has champions that fulfill every role, let's say you have a duo ADC bot, hopefully your team composition is similar to this:
- Renekton Top
- Vi Jungle
- Swain Mid
- Jinx ADC
- Thresh ADC

You've got three relatively tanky teammates that cover your ***, while Jinx operates as another punishing damage-dealer but also functions as bait to protect you, and vice-versa.


Another IMPORTANT NOTE:
WHEN DO I ENGAGE?
When you are in a 2v1, 2v2 (Bot Lane), 3v2, 4v3, 5v4. These are the safest bets. Make sure your team is WITH YOU before you engage.



There are many ****py things that happen in ranked play, even in normal queues, these things will be discussed another time. Anyways, thanks for reading this guide! <3

RawR518