Soraka can prevent an all-in by placing her Silence E on herself as soon as you engage. Try to bait the Silence E out before looking for the all-in.
To increase your kill pressure in a Soraka matchup, focus the Soraka rather than the ADC. Focusing the ADC will not be helpful as Soraka can just heal them with her W.
If you benefit from it, try to get an early Executioner’s Calling. This will reduce her healing ability and increase your kill pressure in lane.
Soraka will go to ward alone during the mid-game. You can abuse this by looking to ambush her as she goes to ward an objective. While she is dead, you could force a fight or take an objective with the numbers advantage.
Invest in an Executioner’s Calling or Morellonomicon if your champion benefits from it. This will reduce Soraka’s healing potential from her W and Ultimate R to help you win the team fight.
As Soraka will be positioned in the backline, it will be difficult for you to take her down fast. To make killing her easier, try to flank from the side rather than running directly towards her in a team fight.
Once Soraka hits level 6, her map pressure increases and she can impact the map with her Ultimate R. Once she is level 6, make sure you ping your team so they know she has her Ultimate R available.
After Soraka has completed Athene’s, her damage output and healing will increase. Expect her to play slightly more aggressive when she has this item completed.
When Soraka has her 3 healing items completed, her healing ability will skyrocket. Make sure your carries have healing reduction items like Executioner’s Calling or Morellonomicon.