The start of the song is one of the more complex and confusing of all Beatle songs. It is subject to almost as much discussion as the opening chord in Hard Days Night. After much research I think I have how it works. If you are counting the song, think of the second note in the riff as the first beat of the bar then it will count correctly.
I tend not to do it like this. I vamp the intro chords a few times followed by a big stop. Then I play the intro riff over a break. The song then falls into place at the end of the lick. I know it is not like the recording, but I can rely on it to work every time.
This is a song with little rhythm playing. It is mostly riff work in the background. Many of the harmonies seem more implied than actual. When I do hit a chord I tend to use some richer chords than you see in many transcriptions. I play with a sharp 9 and a 6 chord throughout the verse.
For the end of the song I like to fall into the La Bamba Riff. I think of it more as the Twist and Shout riff. You will often find me hiding song references throughout an evening. This is a clear one of those references. It makes for a fun ending to a fun song.