Watch the Stop Sign online guitar lesson by Robbie Calvo from 50 R&B Licks You MUST Know
A great way to improvise over R&B progressions is to use double stop runs. This is a great lick using major and minor 6ths on the 2nd and 4th strings. Sliding into these ideas adds a nice touch as well.
Be careful not to get your majors and minor mixed up!