Clogged drains and pipes are a common occurrence in residential homes. Fortunately, it's relatively easy to troubleshoot these issues on your own.
Toilets
If your toilet won't flush, use a plunger to push anything stuck through the system.
Showers/Sinks
If your shower or sink isn't draining properly, there may be debris blocking the pipe. You can purchase cleaning tools in many hardware stores, which are designed to clear these out. Be careful not to use caustic chemicals that may damage your home's plumbing system.