Hi Dermot, thanks for posting this question! Trills and tremolos are an absolutely essential part of this style and you can hear them in almost every song. I would suggest practicing the right hand separately and slowly, until it becomes somewhat automatic in and of itself. When you can do it quickly and mindlessly, then combine it with whatever left hand you know best. Then when you get the hang of playing it without thinking about how to execute it, combine it with the left hand of your choice.