1. Plumbers friend.
I always start with this. Use it when the tub is full so you have a column of water to rock back and forth. Put your back into it, man! If there is something lodged sideways in there that collects hair, you might be able to dislodge it with effort.
- Consider hot water.
If you suspect it might be a grease clog from the kitchen you could try hot water. Get a big kettle of hot water and bring it to near boiling then pour it in all at once. If it is grease that should liquefy it and let it clear.
3. Clog remover. If I suspect hair clogs I usually start with bleach because I always have some and it is cheap. Be generous. I buy no splash bleach which in theory should be better because it is gooeyer. Alkaline stuff like lye or sodium carbonate should work for grease or soap scum. You should not mix different drain cleaning chemicals. Let water flow between each effort.