Try to make some significant part of the composition out of focus. The
classic portrait technique is to select a very soft blurred background
designed to escape attention but this mandate calls for a bit more focus
to the OOF area.
It isn't necessary to have a fancy lens, selection of low contrast
backgrounds can provide smooth out of focus rendering on any lens,
except perhaps slow ultrawides. It can be interesting to play with bad
bokeh too like cats-eye vignetting, freaky donut effects or any
highlights that make a clear disc can add dramatic accents which
contribute to the composition as we often see in movies. Or extremely
soft swaths of blur from a long lens with a detailed item in the
foreground for contrast.
