Watch the ii V I vi Etude Level 1 online guitar lesson by Vicki Genfan from Open Tuning Handbook: Rhythm

Check to make sure you're using the correct RH fingerings: thumb (p) on strings 6, 5 & 4. It may take a while to get used to these fingerings, but in time you'll experience more ease of playing and a smoother RH movement over all. Also be sure you're playing the correct bass notes: The ii chord (Em) root is on the 6th string, the V chord (Asus) root is on the 5th string, the I chord (D) root is on 6th string, and the vi chord root is on the 5th string.