You may wish to review Shifting before continuing with this lesson.

Relative Positioning involves preparing the fingers of the left hand, ahead of time, over the strings they will play after the shift.  Ideally, the only thing you want to do once you get to the new Position is to drop the fingers on the strings over which they have prepared.  This makes shifting simpler and more accurate.

In the first example, the 3rd finger is required to be in Third Position as of the third beat.  Because this is a two
fret shift, it should be Relatively Positioned over the 1st string in third fret prior to the shift.  This allows the shift to bring it to the "A" on the third beat.

Example 1

In Example 2, there is an opportunity to Relatively Position three fingers prior to the shift.  At the end of the first measure, the only finger still occupied is the second finger.  It is currently in Second Position (II).  The shift will take the left hand down to First Position (I) one fret away.  Therefore, the first finger prepares over the F# on the 1st string, the fourth finger prepares over the D# on the 2nd string, and the third finger prepares over the G# on the 6th string.  The shift takes care of everything else.

Example 2

Obviously, any fingers involved in Relative Positioning will need to be prepared ahead of the shift and the exact moment of preparation will vary from one passage to another.  Usually it is a good idea to prepare the fingers when the left hand is not busy depressing strings or clearing off of them.