If you find a certain killer OP, try playing as that killer
So I see a lot of survivors asking for nerfs for certain killers, such as spirit. However, I believe a lot of those survivors have not played enough as that killer. If they did then they would know the strengths and weaknesses of the killer, probably wouldn't be asking for nerfs.
When you play a certain killer you learn their strengths and weaknesses over time. With this knowledge you'll know how to play against that killer, and have an idea how to counter them when playing as survivor. As well as having an understanding of how that killer is likely to think, further increasing your chances of out playing that killer.
For example, a lot of survivors don't like playing against Doctor and consider him OP. However, I'm a Doctor main meaning I have a lot of knowledge on the Doctor's power.
As I've played a lot of Doctor, I know the Doctor's shock has a (around) second delay, in that delay the survivor is still able to vault or use a pallet. So if the Doctor mistimes their shock, I can still make the vault. I also know which loops the Doctor struggles with, even with his power.
This transcends to all killers, even with a Spirit with Stridor. As if you play Spirit you'll have an understanding of her power. Meaning you can work out when the Spirit can use their phase, and a rough idea on how long they can phase for.
As well as having idea of what the killer is thinking, increasing your chances of predicting the killer correctly.