Remove visible hair and debris from the drain opening
Use a plunger over the drain and create a tight seal
Fill the tub with enough water to cover the plunger cup
Plunge vigorously several times
Remove the drain stopper and clean it
Use a drain snake or zip tool to pull out the clog
Pour hot water down the drain
Add baking soda, then vinegar, then flush with hot water
Clean the overflow plate and linkage if accessible
Remove and clean the P-trap if the clog is under the sink
Reassemble parts and test the drain
Repeat the process if needed
Call a plumber if the clog remains or water backs up elsewhere