The foundation of Dancehall Reggae Music is the Drum n Bass, after you have a solid foundation everything comes up by default, you can use a lot of compression on their bass lines and kick drums almost the same for the New York style, keyboards are the rithym part, most common structure is without bridge, most of them use a Third verse as a M8, they uses the lead melody on the chorus part and drops and mixes on verses, theres many dancehall styles, you can identify your self with 80's style it's with the 1 2 rock beat, or you can use the 90's style 3-3-2 or 2ks style with the accent on the first beat, most common sounds are strings, pianos, organs, squares, orchesta hit, brasses, in order to get a good vocal the techniques are differents, they uses one lead vocal, some chorus backing up the last word on the phrase and a backing vocal track filling spaces between lines or words. These are some tips for a Dancehall song.