How to Support (With a Blitzcrank focus)
While it may seem like an easy task, playing support is actually the hardest role to fulfil. You may think that all it is is healing your ADC and getting bossed around by them but this is not true. While your ADC is using "skill" to farm minions you have to poke the other ADC and stop your ADC from being hit. You have to make almost all the decisions in the lane because you are not busy trying to target the minions. If you see someone ganking then you have to tell your ADC to get out of there because he or she will most likely not notice until it's too late. When you destroy the first turret you also have to balance all the risks and rewards because it will be much easier to gank you if you are pushing the second turret. The best thing to do once you have destroyed the first turret is to either let the other team push so you can just have an easy farm or you quickly push far and then rotate to mid. Once you are in mid you try to get a kill and if they leave or hug the turret you need to just hit the turret. If you do not manage to kill the turret quickly then you will have to go back down to bot. You also need to make sure that you place wards in the bushes around bot lane so that you do not get ganked or so you know that a gank is coming.
This will be a more focused Blitzcrank guide. At the start of the game if your team agrees then you need to all go towards the enemy jungle. Make sure you (Blitzcrank) are always at the front and make sure your team knows that you need to be at the front. Once you and your team are in their jungle you need to try to find the enemy jungler. You target the jungler because they have an impact on the whole map so if you kill them then they won't be able to get level 2 as quickly and then they will most likely get flamed by their team for not ranking. If their bot does decide to give them a leash then they will be behind as well. Make sure that you start with your Q so that you can pull people in if they try to run away. Once you get to level 2 upgrade your E so that you can knock people up. Now you want to try hook the ADC with your Q. If you land the hook you need to make sure that you press E straight away so that you actually hit the person and stop them moving for a bit longer. This will allow you ADC to deal more damage before they start getting hit and you will most likely win the fight. Make sure that you always max Q -> W -> E because upgrading the Q makes you deal much more damage and the W increases your movement speed and attack speed. Upgrading E only reduces the cooldown by a little bit so it is not as useful. If you are going very well down bot lane then you may want to consider ganking mid. Make sure to tell them you are coming because the other team could have warded the bush and then you will just be wasting time.
When you get towards the late game (20 ish minutes, when people usually start grouping up) you want to make sure that you are always with your team. If you walk off without your team then either they can get killed because they don't have your backup or they can kill you and then go after your team knowing you aren't there. You need to be the one that tells your team what to do. If there is someone coming up behind you or from the side then you have to tell your team either using the chat or by using pings (v click). If there is an opportunity to hook one of the other players then you should usually take it unless that person is the tank. If you pull the tank that will just give the enemy team a good opportunity to kill your team because you will all be focused on the tank. Once you have pulled the champion you need to press E straight away. Doing this will knock them up straight away and then your team will be able to deal damage without needing to worry about taking damage or getting CCed. If the enemy team engages then you want to press W to run towards them and use your ultimate to try to hit as many of them as you can. This will deal damage and also silence the enemy team for 0.5 seconds. (This doesn't seem like much, but can easily stop a Katarina ultimate from taking out your whole team. GL HF and I hope that you become the best support you can.