Before fixing any load-bearing structures to the wall (such as shelving, wall art, paintings, etc), there are some important considerations to bear in mind first. Consider the type of wall and choose the appropriate plug. Remember that not all wall structures can hold what you want on put on them and if they do there may be a restriction on the location.
For instance it isn’t always possible to put a shelf or a heavy mirror exactly where you want it when the wall isn’t brick. With plasterboard and old lath and plaster walls it is best to try and secure fixings to the wall stud.