What are the best practices for adjusting derailleurs on bikes for optimal performance?

To adjust derailleurs on bikes for optimal performance, follow these best practices:

1. Start with the bike on a stable stand or upside down.
2. Shift to the smallest chainring and smallest cog.
3. Adjust the low limit screw to align the derailleur with the chain.
4. Shift to the largest chainring and largest cog.
5. Adjust the high limit screw to align the derailleur with the chain.
6. Fine-tune the cable tension using the barrel adjuster.
7. Test the shifting by riding the bike and make further adjustments if needed.