Most of the time that will work for minor type of clogs. If it's still not cleared move on to the next step; you will have to make sure the floor of the shower has no water in it by soaking or mopping it up somehow. Boil a pot of water and poor it in the drain, you can also try adding a mixture of water with baking soda or even pour about a quart of straight vinegar into the drain to dissolve the blockage.
For the tougher or deeper clogs, get a plumber's auger from a hardware store.
Hopefully that should have worked for the clog, retrieve the cable back, then run several gallons of hot water down the drain. Finally, replace the strainer screen plate on the drain.
When you are having more serious type of drain clogs that will not unclog with those techniques used, you should call up a drain cleaning company that specializes in drain cleaning, they are much cheaper and do better jobs than the licensed plumbing companies.