Remove any visible debris from the sink drain
Plug the overflow opening with a wet cloth
Fill the sink with a few inches of hot water
Use a plunger over the drain and pump firmly
Remove and clean the sink stopper if accessible
Place a bucket under the P-trap
Unscrew the P-trap and clear any blockage
Flush the trap with water and reassemble it
Pour baking soda into the drain
Add vinegar to the drain
Wait 15 to 30 minutes
Flush with hot water
Use a drain snake or zip tool to break up the clog
Repeat as needed
Avoid using chemical drain cleaners if possible
Call a plumber if the clog remains or water backs up elsewhere