You don't need to know everything about plumbing, but it's important to understand the basics, especially when it comes to leaks.
Tip #1 Wrap your pipes in heat. The important feature is the exterior piping. If the cold-water pipes touch the exterior portion of the building, when the water isn't being used and the temperature is very cold, most likely the pipes will freeze.
Tip #2 You may not know what's right, but you can usually spot what's wrong. Take a quick look at any visible pipes in your house, just to keep up on what's going on with them. Homeowners often don't routinely check; then a puddle of water appears in the basement, damaging their valuables, and they had no inkling that anything was amiss.
Tip #3 A stuffed sink can easily spring a leak. Under your kitchen sink, just take a peek every once in a while and see if there are any drips. It's always a good idea to take a look.
Tip #4 Set back the spigot valve. In some cases, a frost-free hose bib should be installed, especially if the pipe is going through a cement foundation. The hose bib allows you to shut off the water closer to the inside of the home to help prevent freezing.
Tip #5 Radiators need a good level and an open valve. The first thing you have to do is check the pitch of the radiator: it should always be pitched back toward the source of the steam. That way, when that water condenses, it can drain back to the boiler.
Tip #6 A leaky water heater is a dead water heater. The biggest problem is that the lining wears away and you get water dripping from the base.
Tip #7 Don't blow a gasket -- replace it. If you have water dripping from the shower spout, most of the time the cause is a defective washer or defective seat within its body.
Tip #8 Trace the trap leak back to the wall. When you have a leak, often it may be on the back side, where it actually connects to the wall, in which case you'll have to disassemble the drain work. Oftentimes you can even tighten it with your hands to see whether the leaking stops. If it doesn't, just use a wrench to tighten it up a little.
Tip #9 Washers and o-rings are much cheaper than a new fixture. If a washer is worn, even though you squeeze it, you may still get a drip if it's defective. You have to remove what's defective, put in a new washer, retighten it, put the handle back on and test it out.
Tip #10 Mechanical faucets never last forever. A faucet is a mechanical thing, so eventually it's going to leak. There's a point at which the faucet is so old and corroded that it will be difficult to get parts for it. A lot of the time it's simply cheaper to install a new one.
Thank you to http://www.diynetwork.com for input on the above article.