Whenever you are thinking of making a hole on a to put up a nice family picture or whenever you are thinking to dig on your lawn think twice about it and do some research about your property. Drilling a wall or digging can be very dangerous because you might hit electrical cords and metal is a very good conductor which basically means it is a very good transport for electricity which allows atoms to flow freely. Once you decide to do this first examine which are safe places and where you would find electric wires.
One common rule is to avoid drilling around light switches and sockets, as the electrical wires can go horizontally and vertically around these fixtures
The trickiest part about hanging heavy objects is that they may require a stud for stability. Hanging a heavy object off a stud can be done, but you need to know how thick the stud is, as well as how the wires are attached to it.