League of Legends (LoL) Question: Team Composition

There are 4 main strategies you could focus as a team. Each champion is better at one or two of them, but most champions can somehow tweak their itemisation to be better at one. This also means each item is often better at one or two of the strats.

• 1) Teamfighting: The most well known strategy, brawl your way up their nexus. Champions that are good at this will often have good area of effect damage ( Brand, Illaoi, Fiddlesticks) and/or good engage, often represented by area of effect crowd control ( Malphite, Amumu), but sometimes it's just long range and/or strong CC ( Ashe, Morgana) or just great one-person nuke potential (any assassin really). The idea is grab as many of the other team members in the AoE CC/damage and kill the damage dealers as fast as possible.
  
  
• 2) Splitpushing: Often done when you realise you can't win the teamfights, ideally planned on hindsight. You send one champion top/bot while the rest of the team pushes the other lane or threatens baron/dragon. Champions that are good at this will often have a way to deal lots of damage to turrets or waveclear on top of some way to escape ( Kassadin, Singed) or force a 1x1 if the enemy team surrounds them ( Fiora, Nasus, Tryndamere). Some of the champions good at this will just have a global presence ultimate ( Shen, Twisted Fate) and if they planned it on hindsight they should have Teleport. You'll also need good disengage on your team or bad engaging on the enemy team, so that the 4 champions distracting the 5 enemies don't get killed while one champion splitpushes.
  
  
• 3) Poke: This one is hard to pull off and it's often not good by itself. You'll need champions with long range damage ( Ezreal, Xerath, Karma), but also some disengage in case the enemy gets too close ( Poppy, Janna). The idea is withering the enemy team to force them back. After they are at a disadvantage you can either force an engage, take dragon/baron (this often mean forcing them to engage you) or take down turrets/inhibitors. This means you'll need some teamfighting or sieging on top of the poke.
  
  
• 4) Sieging: The least well known of all. Generally -if not only- seen in poke compositions (siege/poke comps). The idea is taking objectives (turrets/inhibitors but also dragon/baron) as fast as possible before the enemy team has a chance to respond and winning by abusing the advantage gained by those objectives. It works well with poke comps because you can force the enemy back without fighting and quickly take the objectives before they return. Champions that are good at this have good range and good turret/dragon/baron damage ( Ziggs is the prime example, Jinx is good too), but it's also important to have some mobility to rotate between objectives ( Karma, Jayce) and some disengage ( Janna) or some teamfighting to properly abuse the advantage gained by the objectives.
  
  - I guess you could name a fifth strategy, mostly done when you're losing: Picking single champions. A "pick comp" should have long range, long duration single target CC ( Morgana, Elise) and/or good single target damage ( Vayne, Veigar, most assassins). The idea would be killing champions that are away from their team. This is a notably strong strategy, especially if you end up in a team with 3 assassins/adcs and no tank (happens way too often), and it's really easy to pull off in lower elos.

As for a definitive article or forum I can't help but I do believe i can shed some light for you.

First off are you playing with a group or solo/duo. This makes a HUGE difference in what you will pick for a comp, i will go over team first.

For teams what are you strengths, do you do well in fights together? Do you split push well, cna you ward and catch people out? This will decide the comp to go.

For team fighting comps its pretty easy. First off you want 2 major ways to engage, typically from top/jg. This include Malphite Rek'sai Lee Sin etc. These people start the fight and typically focus their back line. Secondly you want follow up lock down. While most of these engage have good cc, you don't want to follow up a malphite ult with a gragas ult. These will counteract each other. This will typically be from the mid/support, Champs like anivia alistar and braum are a few examples. Next burst damage. This is similar to follow up lock down, but is more important of damage, Champs like leblanc, twitch,kog'maw, and talon are good examples. Last is DPS (damage per second) This is 99.999% of the time the adc or rarely the mid lane. After the engage you need damage to continue on long sustain amount. Many people fall into the eternal wombo combo. Having a full burst comp and wam bam can be difficult as their team may just spit push so you can never get a clean ace and take towers.

Team comp is mostly a question you need to ask your team. Do we have a good engage? hard cc? peel? do we have a strong split push? Are we god at poking them out? playing around your strenghts will make a much better team comp then simply copy pasting that epic montage you saw on youtube. But a simple formula is as follows
-Team fight comp you need multiple engages and hard cc
-Spit push you need heavy wave clear and sustain
-Poke comps you need hard disengage and at least 2 kinds on LONG range poke
-Solo q what have people selected? Pick a champ your comfortable with that can fit into your comp, or if you are towards the first to pick, choose someone that is flexible enough to fit into a few different roles.