
Jasper D. answered 07/22/19
Professional Freelance Musician and Music Educator based in NYC
There are many ways you can go about this. Firstly, consider the instrumentation you'd like to use. If you're arranging for multiple melodic instruments consider writing melodic phrases (eighth note lines) then harmonize them using different voicings. Another option is to take musical information from an existing improvised solo (ella fitzgerald/oscar peterson/anyone really) and compose your own "written solo" then harmonize that over the proper chord changes for the song.