Watch the Feelin' Fine online guitar lesson by Brooks Robertson from Essentials: Boom-Chick Fingerstyle Etudes
As we take a closer look how to play all the parts of "Feelin' Fine", there will be frequent use of slides, often a semi-tone, with both chord shapes as well as melody. Take note that the thumb is sometimes played very articulately when alternating on the bottom three bass strings as we're used to doing, but it sometimes is played "heavier", brushing up to the G string, occasionally even lightly brushing the B string. Be sure as you work through the arrangement that you've got the correct fingerings to guarantee you're playing the song in the easiest, most economical way possible, which will also contribute to an overall smoothness in your playing. Once again the bass strings should be muffled, while letting the treble strings (where the melody is played) sustain clearly. Try to take sections of 2 - 4 measures at a time and only work that section until you have it down and memorized, then move on to the next measure(s), and so on. Finally, don't forget to reference the tabs and notation.