Im a diamond sona OTP player from EUNE server, peaked top 30 eune sona players and top 150 sona world. here is my opgg https://eune.op.gg/summoners/eune/paparoyNA im trying to improve and i believe i can hit challenger in the following season.

Sona in my opinion is the best enchanter support for teamfights especially front to back ones, he can peel at the same time multiple teammates making her very usefull.
if she is not fall behind she is always relevant and one of the most important persons in the fight. if she stays alive then the whole squad stays to. to the cons tho she is very vanurable, especially in laning phase when she can get easily punished if not played correctly.

At early game what i like to do is guard my jungler entrance eihter the mid one or the tri bush, and i always look to early poke someone before lane starts to get gold and manaflow band stack, most of the times nothing will happen and you will go at laning phase, before you go you always have to have 2 stacks on your passive, to do that when you enter the game you use q twice, so the third one is the empowered one, in lane when you find a good opportunity you want to trade with the adc or support always depend on the situation, to auto them q then auto for a good chunk and 60 gold at your support item, you want to find moments to trade when you either going to get the same dmg or less, never more. you want to trade favourably or at least fairly. after the first trade you auto and q poke whenevher is safe and whenevher you can the enemy bot lane, and you use your W only when your ADC gets dmg so you get double stack on your passive, your goal in lane is not to win it, althrough you are going to try it, but to get as many stacks in your passive as possible without duying, at 15 mins you should aim for at least 60-70 but that depends on how lane goes and how many skirmishes you have fought. overall your goal at early game is to get as many stacks as possible without duying and if possible kill the enemy bot.

when the laning phase is over group with the stronger player on your team and work on objectives, like drakes heralds and towers, as support its good to short call a lot and lead your team with your macro to the right decesions. if you are loosing then you again stick with the strongest person and you try to find peaks at the enemy team taking the shutdowns, and trade objectives, dont contest them if you cant win the fight. make sure you ping those things, althrough in higher elos are thing that most of them know.

at late game you want to teamfight, avoid random 2vs2 or 3vs3 if you dont win those, try to play for objectives and make sure you wont die,

as sona you dont roam a lot, you need the experience a lot. the best thing you can do is to roam mid after base or top depending on how thing goes, but most of the time you will running bot. its okay to match enemy support roams if your jungler is ahead, and you win 2vs2 or 3vs3.

for peel or engage tool, try to not use much flash+R combo, unless its very big ultimate like 3 or 4 persons, or a person you need to kill in order to win the fight, dont flash R when you will die after that, you need to put your safety first and position well. most of the times you going to use R as peel tool when someone goes in to the person you peel to. obviously you wont R an udyr running to your aphelios, unless is nessacary. you will want to keep R for big threats for your carry or the player who is most fed with. always prioritize your safety first, you need to position well all the time, if the person you peeling for missposition a lot dont die with him.

when you trading you want to use the Q power chord, when you fighting a 2vs2 or a teamfight you want to powerchord W the enemy carry or the person doing the most dmg, power chord Q someone who is tanky or you want to burst down fast, and power chord E someone that you want to slow him down or as setup before you R them so you increase the chances of hitting your R.