Travis picking is the alternating-thumb pattern named after Merle Travis. It sounds independent: your thumb plays one rhythm, your fingers play another, and somehow they fit together.
Deep-dive guide
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A longer write-up with every detail, drill, and common pitfall.
The thumb pattern
For a G chord, your thumb alternates between low E (3rd fret) and the D string (open). Quarter notes, steady:
beat: 1 2 3 4
thumb: E D E D
That's the whole foundation. Loop just the thumb for two minutes before adding anything else. Get it on autopilot.
Practice metronome
70BPM
70 BPM. Just the thumb. E-D-E-D. Don't move on until this is automatic.
Add the fingers
Once the thumb runs by itself, drop in the fingers on the "and" of each beat (the upstroke between beats):
beat: 1 & 2 & 3 & 4 &
thumb: E D E D
fingers: M I M I
So: thumb-middle-thumb-index-thumb-middle-thumb-index. The middle finger plucks the B string, the index plucks the G string.
Why this is hard at first
Your two hands are doing different rhythms. Brain protests. Solution: practice each hand separately, slowly, then layer them. Slow is fast; rushing creates patterns you'll have to un-learn.Drill it on G, then C
Spend ten minutes on G. Then try the same pattern on C (thumb on A string + G string this time, since C's bass is the A string).Next: capos. The acoustic guitarist's cheat code.