Watch the D sus 4 Tuning online guitar lesson by Vicki Genfan from Essentials: Open Tunings
In the first section, when playing the single note descending scale phrase, see what works for you - you can pick each note or you may want to do some pull-offs. Notice the middle finger of my left hand subtly muting the 6th string on the C#m11 chord in the second section. Can you do that? It's a great skill to have. After a while it becomes second nature!