Watch the Single String Approach online guitar lesson by Jason Loughlin from 1-2-3 Country
The single string approach has us building a progression with the roots of each chord all starting on the same string. This is very simple because most of the time you don't to change chord shapes but doesn't always make for the most pleasant voice leading. The IV chord is two and a half steps higher than the I. The V chord is a whole step higher than the IV.