Mrs. Robinson - Simon and Garfunkel, song example
For David Bowie's Space Oddity and Seals and Crofts' Summer Breeze there was more production in the recordings than in this recording. 

This recording of Mrs. Robinson was done in one take but I thought I could get away with one mic and make the guitar and voice sound balanced. But as it turned out the vocal drowned out the guitar so much that I decided to record a second guitar part and combine the two recordings. If you listen carefully you can hear a duplicate guitar part in there. I tried to match what I was doing exactly. It sounds like a chorused guitar part, which works great.

For Space Oddity and Summer Breeze I played the guitar by itself, then recorded the vocal, the bass, and then overdubbed guitars as I thought they were needed.  Every aspect was recorded separately. I thought that it might be a nice touch but what was missing was the song example of one guitar and one performer.

It seems that most of my followers are beginning and intermediate guitarists, with some advanced guitarists here and there, working on their skills in some way or another. Singing and playing guitar at the same time is a skill that is difficult to master and it takes time. It takes an understanding of where the beat is in both the guitar and vocals and how to mesh them together. 

When a vocal is present in a song usually that is the most important aspect of the song and the guitar part should be simplified to make space for the vocal. When the vocal drops out then the guitar becomes the main focus. The better you are at playing and singing the more intricate the guitar part and vocal part can be. It's great when a single performance sounds like two independent performers. I'm always striving for that. 

The guitar lesson will be out soon.
Hal

https://youtu.be/uYiYC5i-168