How do I unclog standing water in bathtub
At the drain site, if water not more than an inch, put i cup baking soda followed by i cup warm white vinegar. You may have to do it more than once.
use a clean plunger
You could use a snake made for this exact purpose. It's a very long tool with "teeth" cut down it's length. Put it the drain as far as it will go. Then twist and pull. The "teeth" will catch all the hair and soap muck from the drain. You can find them in any home improvement store like Menard's, Lowe's, etc. Effective and inexpensive.
Tweezers to pull out the clumps of hair in the drain. Be prepared- it is gross. Have a container to put it in.