A piece of advice I often give to people asking about composition is to frame wider and then crop in post processing. This gives more options for trying different ideas, like cropping to a wide format or down to a square because it is much easier to take away than to try and paint back in sections you never captured in the first place.
However, one area this won't help with is the
juxtaposition of multiple subjects in the frame. Unless you are a long way off and your subjects are placed close together, a small shift will make a big difference to how they fit together.
Compare the two shots I took yesterday. Neither are brilliant photos but they both feature the same three stone crosses (and other elements):
The difference between them is a small step to the left and a small rotation to keep the one of the crosses in roughly the same position. That is something you won't fix with clever cropping.
Therefore, when composing shots, move around a bit and compare different viewpoints. Preferably, even take multiple shots. That should give you plenty of options when you get back home and also give more chance of finding the best possible juxtaposition of subjects.
Wulf