The Bass Strum style involves the right hand thumb (p) picking a bass note and then strumming other notes within the chord, also with the thumb. Bass notes are the notes on the 6th, 5th and 4th strings. Instead of strumming the complete chord for every beat, try picking the bass note of the chord on the 1st and 3rd beats and strum the first three or four strings of the chord on the 2nd and 4th beats. Play the following bass note rhythm holding an G chord shape.
The best bass note to pick is the lowest note of the chord that has the same letter name of the chord, called the root note. Some basic chord examples are shown next.
Practice this bass strum technique on each chord separately at first, and remember to hold the full chord shape even though you are not playing all the strings