Depending on your place in pick&ban order, you have to pick accordingly. It isnt the best choice for your winrate to always pick randomly between whats standard, or pick whatever you want regardless of what was already picked. I will describe the process of finding a correct support pick. Written at 2016-08-03.

Picking a support according to pro metagame seems correct in this case. Pick something that works regardless of who is ahead in the game. Its important that their skills are reliable and don’t need many levels or gold to be useful. Current examples of picks that work even with little gold include

Alistar – Q, W, R strong in lategame

Braum – Q, W, E, R strong in lategame

Karma – E, R+E strong lategame, Q , R+Q strong earlygame

Sona – W,E, R strong lategame, Q,W strong earlygame

These supports along with a few other like thresh, bard can be picked at any point in draft and likely fare well. They might not always be optimal, but they tend to be stable and versatile enough to give you a fair chance in any game.

Important note, especially for beginner players: In the beginning, its risky to pick agressive supports with no sustain (brand, velkoz, annie, zyra, nearly any support that you would build mostly damage items on) since you don’t know the lane matchups yet. Supports building damage rely on doing well and accelerating in gold at early game, which depends significantly on your lane matchup which you don’t know yet. If you pick an agressive damage oriented support but end up matched with a weak laner, your picks potential might go to waste. The 2v2 lane with this type of support will become very volatile and prone to one sided results. Any ganks and dives are very likely to work well against those mage supports. At the same time, their gank follow for their own jungler tends to be significantly weaker , relying on skillshots , flashing forward and is focused on damage moreso than on CC early, which tend to be weaker. Its better to save those picks for games where you have a later pick, or when you consider yourself a very strong player with them already.

Picking a more specialized support using your experience becomes possible . Current examples depending on the type of champions picked already include playing :

Against poke – Notably Braum, but also shielding and sustain supports like Soraka, Sona, Karma, Nami or with strong engage – Leona, Blitzcrank, Thresh. You sustain or block the poke until you push yor opponents far enough to take an objective.

Against assasins – strong CC supports with simple disengage or lockdown skills for close range – notably Alistar, Janna, Thresh, Tahm Kench. You wait near your backline for the opponents to engage and then disrupt the attack with CC .

With poke – defensive supports with disengage or shields/heals (Janna, Sona, Bard, soraka, nami, karma) You help your team kite backwards and help disengage from any engage attemps.

With assasins – tank supports with cc (Alistar, Braum, Thresh, Leona) You stay in front of your backline to protect them , and sometimes play flexibly and engage a fight for your assasin to join.

With tanks – sustaining supports (good value with high resistances on a tank) or damage supports (less risk in a teamfight, easier time coordinating a fight)

Weak earlygame of your ad carry – strong earlygame supports like sona, karma

Picking off meta supports at this point becomes viable if you have any good enough ideas and experience to back it up. By the time you are around last pick, its time to evaluate what type of setup did both teams draft, and what its win conditions are likely to be. You can then

counterpick the opponents team – examples include picking braum against ezreal jayce and viktor, picking alistar against yi , zed and fizz.

pick for synergy with your own team – examples include tahm kench for a protect AD carry comp, a tank to make fights easier to play for your team and you dont have one*, karma for a speedy pick comp.

counterpick the enemy lane . Since you know at least 1 of the opponents in lane and likely know what your ad plans to pick, you can pick a strong laning support to help a weak ad carry, take away a champion with strong synergy for opposing ad carry (for example take braum when opponents have lucian) or counter the opposing support or ad carry in lane (example is taking sona against vayne + alistar to dominate a lane, taking leona with ignite against soraka to threaten her with strong all ins)

pick to balance your teams early or late game – if your earlygame is weak pick sona, karma to keep your team afloat. If your team has little damage and you are playing 2v2 against weak laners you can pick zyra, brand, velkoz to add a punch in lategame with less risk of throwing the game early.

*From my experience in D5, most people struggle when playing lategame teamfights without a tank. Games without tanks on one or both sides tend to be decided quite randomly by people dying for disrespecting fog of war or playing badly around it. When not grouped, its difficult for people far away to join a commited fight on time (a non tank will die before a teleport is finished) and while grouped, many players have trouble fighting before someone commits, sometimes leading to a team getting poked or killed for free while everyone is running away, or engaging late when already at a HP disadvantage. Therefore i recommend that you play a tank everytime your team lacks one, untill you find yourself high enough for that to not be an issue (i’m assuming it happens somewhere significantly higher than where i am at – perhaps at challenger level)

Summoner spells should usually be exhaust and flash. Ignite works well if you are playing a tank support where ignite would give you kill pressure (notably against soraka in lane) , when you have a significant 2v2 matchup advantage and don’t need exhaust to win it heavily, and when all opponents damage dealers are long range and unlikely to be found in range for an exhaust before unloading their dmg. Mage supports, although very tempting with ignite, tend to be more stable with exhaust (especially when getting ganked)

Runes should give you a better chance at winning the laning phase, with flat values instead of per lvl or % ones. standard setup is hybrid pen marks, hp seals, armor quints, ap glyphs/quints on squishies. For tanks its usually ad marks, hp seals, mres glyphs, armor quints. If you are the only tank or no tanks are present, i recommend using less offensive and more defensive runes.

Item build for every support should be centered around sightstone, swiftness, mobility or lucidity boots, upgrading your initial support item. After that its situational (usually – locket, mikael for utility, possibly frozen hearth, banshee, GA as standard defensive items, for mages rylai and zhonya/void staff).

Use the yellow trinket before you have sighstone, after you get it use the red sweeper. After lvl 9 upgrade your red trinket. Squishy supports , especially while losing the game should consider using the blue trinket, especially if team doesn’t help you sufficiently with vision. Buy a pinkward every back regardless of your champion untill your last item. You should place at least around 1 pink every 5 minutes (dont leave it in 1 place like the bot tribrush for the entire game) and at least 1 ward per minute in any game you play.

Most champions have a cookie cutter mastery setup. In case you arent sure, the most stable option is to go with

0/18/12 (movement speed, biscuits, mana regen, bandit, 5 % cdr, TLD + hp regen, damage reduction, 50 hp, summoner spell cd) [mage supports]
0/12/18 (movement speed, biscuits, mana regen, bandit + hp regen, damage reduction, 50 hp, summoner spell cd, 15 % tenacity, bond of stone) [tank supports]

No pick will give a sure win, however in my experience there is significant value to picking a correct champion at a given point in pick&ban phase. One of the most common problems of support players is picking volatile champions early in the draft with little ways to get back into a game, relying instead on 50-50 outplays early to stay ahead, or receiving no ganks from the opposing jungler. Picking stable champions early in the draft,and more specialised to counter or synergise with other players later on seems to be a key factor towards winning a game in my experience. Stable champions built correctly will give you more opportunities throughout any game to reverse it or close it out, while specialised counters built according to your teams needs or enemy teams weakness can give you a window of significant advantage in early, mid or late game. Whatever you pick should either be resistant to disadvantages, or likely to gain an early advantage big enough to justify its late game weakness.