question/
Without looking at a specific op-amp, these are my suggestions/comments:
Since Power Supply Rejection Ratio is the Gain from the power supply to the output rejected by the open loop gain of the amplifier:
1. Make sure you have a high open loop gain
2. Power supply noise coupling to the signal path are common mode signals where possible.
3. Have a symmetrical architecture
4. Choose a wise compensation scheme to avoid power supply coupling to the output.