"San Antonio Rose" is a classic country song that features a variety of chord progressions across its different sections. It's a good song for beginners to learn as it has a relatively simple structure and a small number of chords, but also introduces some more complex chord changes.
The song begins with an intro that cycles through the chords D, G, G#, and A. This might be a little challenging for beginners, as transitioning from G to G# requires a quick shift of the hand position. Try practicing this chord change slowly at first to get comfortable with it.
A simple downstroke pattern (down, down-up, down-up) should work well for this song. The slow tempo of the song allows for a relaxed strumming style.
Pay attention to the transition between G and E7 in the verses and chorus. This is a common chord progression in country music, and mastering it will be useful for many other songs. Practice transitioning between these two chords to smooth out your playing.
In the bridge, the song introduces the A7 chord. This is a relatively easy chord to play, but it might be new for beginners. The A7 is essentially the A chord without one of the notes, creating a more 'open' sound.
The song also features an instrumental section, which you can use to practice your picking skills. Try picking the strings individually instead of strumming to give this section a different feel.
Lastly, the outro of the song repeats the last line three times. Vary your strumming pattern or dynamics (how hard or soft you strum) to add some variation and build intensity towards the end of the song.