As good pictures talk for themselves, it is always a nice idea to add pictures to your wall. For example we often see pictures of beautiful fruits in the dining hall and pictures of great musicians and musical instruments in a concert hall. Lots of things help in deciding to set up your picture frames like your common sense, preference, current trends going around, etc.
Firstly give a bit notice to scale. Give vast picture significance and let it rule the wall. Another beautiful arrangement from the mid-twentieth century is slightly overlapping two pictures diagonally with a frame overlapping the other frame. You can even hang three set of pictures symmetrically. If you are going for four pictures then those should be hung in a straight manner or in a block way. You can even design a picture wall by adding group of photos, mirrors, sconces, etc. All you need is to devote concentration to the shape of the picture order.