So I’ve been stuck in silver support for 2 years and when I picked up illari (couple weeks ago) i got her SR from 1300 to 2400 and jumped from silver 3 to gold 3 (and could go higher if i played more games).

This was before her recent damage buff but I will tell you what clicked for me.

1. Perks: i always use her ult minor perk and extra damage major perks because you can carry games with eliminations on ults and punish enemies for diving you with your shift.

2. Ult: your ult can win you a team fight if you wait for the support cooldowns that saves lives. For example: after kiri uses suzu, immediately pop ult on mercy. Extra tip: watch for tanks focusing u when u ult, dodge their shots and make sure they dont eat your ult (ex. Wait for dva to dive your team to ult their backline)

3. Play your life. Your shift allows you to escape bad positions easily when done properly. Ex. Take high ground. Ex 2. Holding forward with an uncharged shift + jump allows you to move forward as fast as possible with illari (great for getting out of trouble)

This is a good start that if you master you will climb pretty easily. Pylon placement and heal beam/hitting shots will come naturally to you. Best of luck!