Hello support players, I am currently a plat support main that has played countless thresh games to bring you this guide. He is one of my all-time favorite champions and as such I felt that it might be a good idea to pass one my knowledge of the champion. Also REMEMBER this build is what I FEEL is best so it may be subject to opinion, however it has worked for me so if you're feeling brave, feel free to come join in the OP'ness and play some thresh. So! Lets get started.

PROS:

Very tanky
Good picks
Strong lane
Free Armor
Insane utility

CONS:

No sustain
If you don't collect souls, base armor is very low
Difficult to play
Lots of skill shots/hard to land abilities

Passive- Make sure to collect all souls you can (be intelligent) because, while Thresh's natural armor is awful, he can quickly become an armored beast by simply moving around if you collect the souls around you.

Q- This is your staple ability. It allows thresh to pick off enemies and gives him a very good engage ability. I recommend maxing this in mid game for the CDR that gives. This is also his hardest ability to land so it may take some practice to get used to.

W- Dark Passage makes Thresh very good at re-positioning his team. I recommend maxing this ability last, because it is something of a one point wonder because its best benefit is given to you as soon as you get it (the ability to move team mates). Throw this little lantern to your team mates who are out of position. Free save when your dumb*** ADC tries to facecheck a bush. Good lanterns save lives. Remember that.

E- Flay is Thresh's best CC ability as long as you're close enough to land it. Take it in lane early and abuse the empowered auto attack in lane (but for the love of god be smart about it don't go try to out harass a Soraka or a Sona.) This ability scales well with AD so think about taking ad runes for this.

R- Pop it in the middle of their team in teamfights and you win. Use it to peel for your ADC. Its a little hard for that Renekton to dive onto your carry when he is slowed by 80%. I would try to put it in places that block of lanes/ jungle paths so the enemy is forced to go through it to get to you and your carry. This ability is easy to flash out of so try ulting then flaying the enemy into your wall.

Q+Q+E- This is the classic superman Thresh ability, it allows him to jump into fights and cause havoc moving nearby enemies to your team. Remember, don't go to ham with this though!

R+E- This is a necessary combo to learn and master. Thresh's ult is easy to flash out of so try boxing then flaying an enemy into one of your walls.

W+Q+Q- If you are looking to carry one of your team mates into the middle of their team or lane this is a strong combo. Simply W where you team mate is then Q your target. Then superman Thresh into your team with the friendly in tow.

Flash+R- Flashing and then using your ultimate directly after can be a very strong engage combo, trapping their team in a slow. Also you can use this to zone their team. This is just a great overall way to start you combos (especially if you add your E to this combo).

Flash+E- The flash flay is one of the best tricks Thresh has. It can set up into his ult, it can push enemies into CC or it could pull an escaping enemy back into your team. This all could go the other way too, you could knock an enemy out of his ult, prevent enemies from CC'ing your team or help to save a fleeing team mate. Definitely keep this combo in mind.

Flash-
This summoner is a must have. Take it every game. Use it to either escape, hit flash hooks, flash ults or even flash lanterns (to save that super out of position kog'maw).
Exhaust-
Take this is summoner if they have a certain adc such as vayne or jinx so you can turn their damage into a joke and make them an easy pick at the same time. Also take this if they have some nasty burst on their team to negate it and save some lives.
Ignite-
If you want to win lane and get early kills, this is the summoner you want. Also take it against people who can ignore exhaust such as Morgana.

This is a list of all viable items and when or when not to build them. I have dived these items into seperate "slots" to show where you should build these replacement items. In the slots , best items come first and are ranked in descending order (first on the list is best). To clarify this a little, no slot is better or more vital than another, simply there are better items inside of each slot.

Slot 1 items: Support Items
1. Face of the Mountain- This is a very strong tank item, giving you lots of early game health and sustain. Build this in almost every situation.

2. Talisman of Ascension- This is also a viable item, build it if you have a very immobile team (such as Nasus, Varus, Veigar, and Volibear to name some). The movement speed is really helpful if your team needs it but most of the time, don't build this item as your early game tank will be very low.

Slot 2: Armor Items
1. Randuin's Omen- This should be a pretty consistent buy. It gives you good peel for your adc with the slow, good stats and a good build path. There isn't very many reasons not to build this unless they are AP heavy or you get really far ahead early and decide to go sunfire cape for the damage.

2. Sunfire Cape- If you get really far ahead in lane and want the mid game damage it has to offer go ahead and grab it. Otherwise get Randuin's instead. Also, don't double it up with Randuin's unless they are 5 AD Champions (and even then, frozen heart and thornmail are better buys).

3. Thornmail- Not a bad item. Has its benefits. But only build if they are heavy AD and/or their ADC or another AD auto-attacker (master yi, tryndamere, fiora, gangplank etc)is really fed. IT IS A MUST BUILD IF ONE OF THEIR AUTO ATTACKERS IS FED.

4.Frozen Heart- This is a solid armor item. You can replace it with Randuin's if their team is very attack speed heavy. Can be a good purchase if they have an attack speed reliant adc (vayne, trist etc) and need to slow them down a little bit.

5. Ohm Wrecker
I haven't had enough time to test this, so I can't put this higher on the list. I do like what I have seen so far with it though. It can stop a tower which is really nice, especially if you and your adc or your jungle is fed, because you can now dive the tower, Also, it helps you move to lane quicker and can help you roam quicker. Plus the build path and the stats from it are pretty good. I like this item a lot.

Slot 3: Locket of the Iron Solari (and slightly Spirit Visage)
1.Locket of the Iron Solari- This is another item you should build nearly every game. The only reason you shouldn't build this item is if they have 5 AD. If that is the case see above and build an extra armor item (I would pick one that has HP on it as this item is a good chunk of where your HP comes from).

2. Spirit Visage- This will help you sustain and give you health, MR, and CDR which are all very strong stats. However, there's no real reason to build this because, locket is essentially the same item but (in thresh's case) better. It has HP regen, MR, CDR and HP with a shield on top of that and an aura on top of that. This item is only really good on champs that heal a lot (Dr. Mundo) but not so much on Thresh. I only am putting this on here because it is viable. Keep in mind that Locket is simply better.

Slot 4: Utility item

1. Mikael's Crucible- This is a very good item to have as it gives you and your team a cleanse from what ever CC they throw at you. I recommend building this item often unless they have a low CC comp.

2. Banshee's Veil- Only build this if they have strong AP nukers (Fizz/Leblanc are good examples)and need the extra stats and spell shield to help with damage mitigation. If you do build this, you will need to change your masteries to contain CDR (you will now take 0/9/21 masteries) to help make up for the CDR you are going to lose.

3. Righteous Glory- I actually really like this item. You can stack it with a Talisman of ascension and use it to help your team engage. Really only get this if your team has lots of movement speed reliant engagers (Garen, Singed, Olaf or Mundo are all good examples) that rely on just running at the other team to get into the fight. I wouldn't build this every game but definitely a good option in the odd game.

4. Warmog's Armor: I would only build this if you desperately need extra HP (maybe they have a lot of burst champs like graves, fizz, leblanc, akali etc) or you desperately need sustain. I would avoid building this as the other items on this list are generally better but this can be a decent item.

Slot 5: Sight Stone
Sight Stone- Should be built every game. Yes, every game. No exceptions. You will always need wards. There is virtually no game where you will not build this item.

Slot 6: Boots
Mobility Boots- Usually the best buy on a support. This is best for being able to ward, roaming and doing you supportly duties. Build these in most cases.
Ninja Tabi- Build this vs a very fed ADC or an AD heavy comp (4+ AD Champions).
Mercury Treads- Build these if you are going against a very high CC comp or a very high magic damage comp (4+ Magic Champions/3+ CC champs, meaning heavy cc champs like nautilus/amumu).
Slot 7: Trinkets
Green Trinket- Build this trinket at first for ward coverage. But usually you are going to want to sell it as soon as you get sightstone. If they have a sneaky champion like evelynn you might consider keeping it and making it into the pink trinket.

Red Trinket- While you need the Green trinket early game for the ward against their jungler, you want to get this after you get a sightstone so you can clear enemy wards. Also I recommend upgrading it early as well.

Support Match-ups:

Good against:
Leona- Flay her outta her Zenith Blade. You can easily prevent her from getting in melee range meaning you can stop a lot of her burst damage and cc. Also, your utility as a support is far superior. Use things like your lantern to get your allies away from her (remember she has to be in melee range for most of her cc/damage) or to move them out of the rest of her cc, her ult. She works in chain combos and thresh is very good at disrupting her combos. Also, if she tries to dive your team somewhere, I would quickly box and flay her team away that way she is stuck solo against your team and her allies can't follow her engage. USE YOUR DISENGAGE.

Blitz- You can catch their adc if he catches yours. Also you have stronger utility and peel as Thresh. Furthermore, you can lantern friends back to you if they get hooked. Try to engage and fight team fights as often as possible as blitz has very little team utility and depends primarily on getting picks to win. SHOW HIM WHO THE REAL HOOK GOD IS!

Soraka- Thresh is very good at forcing instant engages and fights, which is what Soraka dreads. This is a situation where you want to focus the support. She is immobile, so very easy to CC, quick to die, and has no self heal/peel. Simply hook her, flay her towards your adc and then ult and its basically a free kill. She will die much faster than you so all you have to do is tank their adc for a moment while yours engages. But don't play the harass game with Soraka or you will lose because she will out sustain you. Her harass isn't as much (not like Sona's or Lulu's) so I doubt she will ever actually kill you but you can waste an otherwise easy won lane and find your self on the back foot if you let her sustain and stay back. FIGHT OFTEN AND FOCUS SORAKA.

Bad against:
Morgana- Her spell shield will eat your hooks for break fast, it will break your walls, avoid your bonus flay damage. And if that wasn't enough, binding prevents you from following your hook, stops your lantern from carrying an ally. This match-up sort of sucks. The only thing you really have going for you is that you are tanky and therefore can eat her CC in the place of your adc (basically just tank up and try to be Braum). To succeed in this lane, try to use flay auto's to break her shield, that way you can actually cc her/her adc. Make sure to flay her away from your team if she ults and be ready to box if she ults a good portion of your team so you can possibly prevent follow up engages from the enemy team. KILL THE SPELL SHIELD.

Lulu- Remember what I said about no sustain? Prepare for harass and if you try to engage prepare to be a squirrel. To succeed in this lane, build a talisman of ascension and just try to land hooks from afar. Just survive this lane, focus on landing hooks from afar and following up with some harass. Don't fully engage unless you hit their adc AND Lulu has no Q (it will slow your adc and you will be left alone as a squirrel/cat/dragon/cupcake/ whatever trying to survive a 2 v 1). DON'T GET POKED.

Goes Even Against:
Sona- This is basically a "can I hook you match-up". If you can't, she's going to poke the **** out of you and sustain her ally up resulting in your loss. If you can hook her, she is really squishy and will die quickly. To win this, hook her or her adc as much as possible and try to avoid long drawn out poke/trade wars. YOU WANT TO HARD ENGAGE ON HER LANE.

Nami- Very similar to the Sona match-up however, Nami has actual CC at the cost of damage. Expect to be poked less but possibly CC'd and killed. I would give Nami the edge in this match-up, but her abilities (her Q really) are hard to land and easy to avoid and she has no real way of dodging hooks so you can win this lane IF you out play her. This is very much a skill match-up. DON'T SUCK.

ADC Matchups:
Good Match-ups
MF- Easy to cc her out of ult and get picks since she has no escapes. This is basically the easiest lane there is especially if you have something like Lucian or Graves to back you up. Just hook her as much as possible and stop her ult with a flay (flash flay is a good combo) or a hook. JUST CC HER.

Lucian- His low aa range makes it easy to harass with flay. Also since he has lost his ability to cleanse slows, Thresh can set up box plays on him easily. Ironically enough, Lucian used to counter him. Oh how the tides have turned! Note that with this match-up, hooks are actually very hard to land because of Lucian's dash. Try to blow his dash early before hooking or, if he dashes out of a hook attempt to land flay (be smart, don't force it or he will just harass you). This is still a hard lane for Thresh, but as soon as you manage to get on top of Lucian, his soul (along with his wife's) is yours. USE FLAY EFFECTIVELY AND LAND HOOKS IF YOU SEE HIM USE HIS DASH.

Because there are just way to many ADC's to put on this list, note that Thresh will generally succeed against ADC's that have a low mobility or low attack range (I will eventually update this match-up list to include all ADC's but for the time being this generalized statement is going to have to be enough xD sorry guys).

Bad ADC Match-ups
Sivir- Spell shields all of your CC

Good With
Lucian- Offensive lane, easy to win and get kills
Twitch- Is good at re-positioning your out of position twitch
Kog'Maw- See above
Any ADC without an escape