So bare in mind this is what MY FAMILY do (Rastafarians) so it obviously doesnt count for EVERYONE anyways
Christmas
Foods/ Drinks
Celebrate by drinking sorrel is dark red, a little sour, with a raspberry-like flavor; made from the petals of sorrel plant (flor de Jamaica)” or hibiscus plant flower as popularly known in West Africa
Celebrate with rum cake A rum cake is a type of dessert cake which contains rum. In most of the Caribbean, rum cakes are a traditional holiday season dessert, descended from the holiday puddings
Music
Listen to Reggae around this time of the year as it represents new life/ new year/ new beginning
Food is the centre of celebration we don’t have any special clothes, any special dances, traditions as such we celebrate ‘normally’ when it comes to new years and christmas
So when ur writing u dont need to do anything specially different to how u would write just an average celebration as the only thing different is food and music. we have presents and santa and all that stuff 
IK IM NO HELP BUT YEAH