tea for two wrote: ↑Fri Jul 30, 2021 8:21 am If we can imagine the bowing hand movements, this helps us in how we write the String parts.
For really effective string writing, in addition to all the useful stuff above about voicings etc, it is well worth getting to grips with the various bowing techniques that are available. There is a lot more to it than meets the eye, and it opens up some more possibilities for arranging techniques. For example 'col legno', 'spiccato', and plenty more.