The first stage is to create the jigsaw, look at all of the potential images and highlight the good bits, then you need to put them all together, blend and merge, tweak to make them look like it was taken as it stands and take a long hard look at your handy work. It takes a good eye for detail, make sure that nobody has 3 hands, a good level of judgement, if it is going to look good, plenty of skill and patience. Some of these can take 3 or 4 hours to complete, but if it results in the right picture it's all part of the service. The camera never lies ... it always lied a little bit.
Being a modern photographer means knowing how to do these things and do them well so that the final image is the one the client wants. Many times I'll make a puzzle fit and the client is never aware, it's only when I show them what I've done that they appreciate the additional effort.