Watch the Top Ring online guitar lesson by Brad Carlton from Chord Studies: Rock and Pop Progressions Vol. 2
This progression is based around a descending bass line on the fifth and sixth strings. The second chord, Asus2 over C♯ could also be thought of as an Aadd9 in first inversion. Work on hyperextending your fourth finger so that you don't mute out the first string. When moving into the C6 try pivoting about your 4th finger - this may seem a bit unorthodox but we do this to sustain the top two voicings. Think about hearing this progression on a keyboard with all of the voicings ringing.