If you can't locate your main shut-off valve, look for individual shut-off valves for your bathroom or shower, often under the sink or behind an access panel. If those aren't present or accessible, you may need to contact a plumber to identify and mark the main valve, or temporarily shut off water to your entire property from the street if you have access and permission. Do not proceed with the project until the water supply is confirmed off to prevent significant leaks.

Many modern shower handles use a small set screw, often hidden underneath the handle, behind a decorative cap, or on the side, which typically requires an Allen wrench. Carefully inspect your handle for a small opening or a cap that can be popped off. A multi-size Allen wrench set is an inexpensive and valuable investment for various DIY projects.

For a stuck shower head, try applying a penetrating oil like WD-40 to the threads and letting it sit for 15-30 minutes before trying again with an adjustable wrench. For a stuck handle, ensure any set screws are fully loosened. If corrosion is severe, using a pipe wrench with gentle, increasing pressure (for metal parts) or carefully applying heat with a hairdryer to expand metal connections might help, but avoid excessive heat on plastic components.

The most common reason for leaks is insufficient or improperly applied plumber's tape. Ensure you wrap the tape clockwise around the shower arm threads (the direction it tightens) 3-5 times, making sure it covers all threads without gaps. Also, confirm the connection is hand-tightened, then given a final quarter to half turn with a wrench, but be careful not to overtighten and crack plastic components.