I don’t know if that is something that can be answered in a single reply. I took Irish harp lessons weekly for 10 years and still have much to learn about getting the dance music right!
I’d say listen to as much Irish music as possible, not just on the harp (Grainne Hambly is my favorite) but other instruments as well to get a feel for the dance rhythms of jigs, reels, hornpipes, etc.
One thing I do know for sure is to keep the left hand simple–the melody is the most important thing. Also as a general rule 5th and octaves are more authentic sounding so leave out 3rds.
Then of course there is the ornamentation–triplets, cuts, etc. Again, listening will help with those, but is there a teacher in your area? Or maybe you can find a tutorial on youtube?