Remove visible debris from the drain opening
Pour boiling water down the drain
Use a plunger over the drain opening
Remove and clean the drain stopper or cover
Insert a drain snake or auger into the drain
Rotate and push the snake to break up the clog
Pull out any debris caught on the snake
Flush the drain with hot water
Use baking soda followed by vinegar
Wait several minutes, then flush with hot water
Clean the P-trap under the sink if needed
Reassemble all parts securely
Test the drain with running water
Repeat the process if the drain is still slow
Call a plumber if the clog remains stubborn