One can either keep the tape on the roll or cut off a small piece. The tape should be wrapped around a male fitting in a counter-clockwise direction. This driection is selected to make sure the tape does not bunch up when the fitting is screwed into the female connection. When tape bunches up, thread coverage is lost and leaks will persist. It is very easy to mishandle the tape because it is think, hard to hold, has a smooth surface, and easily becomes entagled.
When wrapping the tape, wrap it around the the thread of the male fitting as least twice. The extra tape provides greater thread coverage. One can try up to four wraps and then check to see if a seal will form by attaching the male fitting to the pipe.
When wrapping is complete attach the fitting to the pipe. Make sure you turn the pipe each using water pump pliers and/or vice grips or a pipe wrench. Turn on the water and check for leaks.
Some tips and miscellanous information:
Note that some people prefer to use pipe joint compound instead of Teflon tape.
Some people wrap more than three times.
Make sure all the treads are covered by the tape.
Don’t apply the tape losely but use a lot of effort to wrap the tape otherwise a seal will not form.
Use less wrapping force on a plastic fixture.
Becareful not to take on a plumbing job that is too difficult or complex. Consider contacting a plumbing professional if you find that you are not able to complete your work
Always be aware of the location of your main shutoff values are for your pipes.