Preparation: 

 Before beginning any work on the shower, make sure that the bathroom, especially the shower or tub floor, is completely dry.  This will prevent accidental slips and will make the work easier.

Gather all the tools you'll need.  In addition to the new showerhead, you'll need adjustable pliers or an adjustable wrench on hand, plush some thread seal tape and some ordinary masking or duct tape.

Read through any instructions that were included with your new showerhead.  make sure you understand them completely and that nothing is missing from the showerhead assembly.  The helpful folks at Sneade's Ace Home Center can walk you through the process and answer any questions you may have.

This simple project doesn't require you to shut off water to the entire house, just turn off the tap and you're ready to begin.

Step 1 - Protect the fixture:  Wrap the grasping ends of your pliers or wrench with masking or duct tape to protect the old and new showerheads from scratching.  Many of the metals used to make bathroom fixtures, especially brass, are soft and easily damaged.  If no tape is on hand, you can use an old leather belt or kitchen towel as a substitute.

Step 2 - Remove the old fixture:  Hold the shower arm firmly with your free hand and slowly unscrew the showerhead with the wrench, turning counter-clockwise.  Take care not to use too much force - otherwise, you may break the shower pipe.  As soon as it is loosened, set the wrench down and finish unscrewing the old fixture by hand.

Step 3 - Prep the pipe:  Clean the existing pipe and pipe threads with a cleanser capable of removing lime, rust and other mineral deposits.  Rinse and dry the threads carefully, then wrap the threads with three to five layers of fresh thread seal tape.  The tape will help seal the pipe against leaks after the new showerhead is installed.

Step 4 - Install the new fixture:  Screw the new showerhead onto the shower pipe, hand-tightening as much as possible before using the taped wrench or pliers.  Only tighten the fixture when a single turn of the wrench - any more than that could over-righten the connection and lead to problems.

Step 5 - Test for leaks:  Run the shower for a full minute, checking for leaks.  If there is a leak, remove the showerhead and thread seal t ape and try again.  If leaks persist, contact the helpful folks at Sneade's Ace Home Center for additional advice.