Im sry if this guide isnt good this is my first guide and i dont yet know how to do the chapters properly , please dont judge me! I have played a couple of ranked games and I have won using the base of this build depending on the different situations.

The marks are magic penetration for stronger early game poke and the ability power quints are so that there is a bit of damage output early-game, the seals and glyphs are to add magic resist and armor so she can take a few hits earlier on in the game.

I put 21 in utility and 9 in defense, altogether soraka gets the benifits of some tankiness and the utilitys help her with mana, cdr, money problems (if she auto attacks she gets +3 gold), Etc.

Try get your boots and the sight stone built first.

The full build ensures you have armor, magic resist enough ap for a crazy-poke support and you have full cool down reduction (40%) so your ulti will be up more often and u will be able to use your abilities faster.

Try to level up your Infuse first because its doesnt cost mana and you can spam it all day (meaning great poke and keeping your adc's mana levels high). Then Leveling up your Astral Blessing and starcall try to ulternate (although your heal is more important to level up first). lastly making sure you prioritise your ulti wish leveling it up as soon as you can.

Situations change very quickly if your poking isnt doing very well then go more tanky as in thornmail, GA, warmogs anything that gives health, magic resist or armor. If you are agaist a really tanky support such as blitz or thresh you will find its pointless poking them, they will just poke you down and stay there and you cant scare them from the lane. You will then have to full out focus the adc (getting mobility boots will be great to run in get the poke and run back dodging any grabs).

PRO'S:
+ has 2 pokes (infuse,starcall)

+ great sustain has 2 heals

+ has an ablity that doesnt cost mana
meaning you're less reliant on mana

+ her starcall reduces magic resist which helps with her pokes

CON'S

+ Quite squishy, normally you picked on
first in a team fight

+ Has no escapes (flash is a must-have)

+ Soraka isnt a very tanky so if the adc doesnt have strong poke/attack or is
very squishy you wont last long in a fight

+ her starcall reduces magic resist +

+ Except for her silence which doesnt slow the enemy
soraka doesnt have proper cc (meaning she cant really start
engages like when you stun and start a team fight).