Remove the rubber stopper from the shower drain if your tub uses one. Lift up the plastic stopper from the drain if your tub uses that style instead. Slide a flat head screwdriver under the metal strainer and carefully pry it up. Be careful not to bend the strainer as you remove it. Set the strainer aside with the stopper.
Turn the water on as far as it will go. Allow the water to run and wash away as much of the clog and debris as possible. Continue running the water until it begins to back up, then shut the water off.
Shine a flashlight into the shower drain pipe and look for visible clogs. Hair, soap scum and other debris can accumulate inside the drain and cause blockages. Place a plunger over the drain pipe and use it to dislodge the clog if you can. Reach into the pipe with a hand snake if the clog is still in place. Feed the end of the snake into the drain and continue until you feel it stop. Turn the snake counterclockwise to capture the clog and pull it free of the drain.
Turn the water back on and run it as fast as you can. Watch as the water moves down the drain. If the water drains properly you are finished.
Pour a liquid drain cleaner designed for use in showers down the drain if it is still clogged. Follow the instructions on the bottle when using the drain cleaner. Replace the strainer and rubber stopper in the shower after the clog has been dislodged.