When I first started making Rosaries, one of the trickiest parts was assembling bead cap configurations on my Rosaries! It was so much harder than it looked. Most of this is due to the fact that there is a nearly infinite number of options to choose from!
The first rule (and maybe the only rule?) of arranging bead caps is that you have to taper them down from the bead. It just looks silly to add bead caps that are wider than the bead itself. You also don't want to just keep adding pieces of the same width, each piece should be slightly narrower than the piece before it, to keep it looking elegant.
Above and below are two examples of this tapered effect with bead caps.
Below is another, riskier option. The Rose beads are wider, but the important thing is that they are still smaller than the bead itself. The important thing is to draw the eye down and away from the bead.
Generally it ends up being an experiment playing with bead caps, so if you are just starting out, it is helpful to either copy an already aesthetically appealing design on your own pieces or to just buy a multi-pack of bead caps, so you have a lot of options to choose from. You'll know right away when you look at it whether the combo you are considering "works" or "doesn't work.