The first thing to know about plumbing is that there are two systems the drains and the water service, reading up on websites about this will get you on your way to becoming a beginner. Make sure you don't just read one article, read around as one may say something different to another. You should always plan what materials will be needed for the job. At any point you feel that you are uncomfortable with the task at hand, call a qualified plumber to come out, but from experience most plumbing jobs are very straight forward.
Common easily resolved problems:
- Finding the stopcock - A stopcock is what will turn off your water. You can normally find one inside your house either under the stairs, sink or airing cupboard and one outside on the street.
- Finding the isolation valve - If you aren't looking to turn off the water for the whole house and just for lets say fixing a dripping tap, then under the sink there will usually be an isolation valve to turn off the water leading to the sink, which can be easily turned off with a flat head screwdriver.
- Blocked Drain - Some drains can become blocked with hair and dirt. If this happens it can easily be resolved with some common household products such as vinegar and salt or purchase a 'Plumbers Snake' which is a flexible metal rod which can be used to hook out some of the dirt.
I hope these couple of points have given you a better insight into the plumbing basics and I hope I have helped.