When you can play these progressions smoothly you should experiment with different rhythms, bass note picking, runs and hammer-ons.
The following arpeggio study uses chords in the key of D, together with bass note runs. You may wish to isolate some of the more difficult chord changes (e.g., bar 1 — 2) and practice them separately. Be sure to follow the pick motion as indicated in bars 1 to 9. The pick motion change in bar 9 is to facilitate the extra bass notes of the run, and should also be used in bars 10 and 13 — 16.
"The Ash Grove" features extensive use of the half-bar in bars 1, 2, 4 and 5; isolate these chord changes and practice them separately, before playing the whole piece through.