I’m not actually adding any extra articulation to those notes. Sometimes I will add a ‘T’ sound but this is not the case In Horses and most other jams and lessons.
What gives the notes that clear professional sound is breath control. In Horses in particular I start the notes with a very subtle volume increase or decrease.. this adds character.
And, of course, my single notes are accurate.
I hope that helps!
Keep on harpin’