Watch the Ska Building Blocks online guitar lesson by Chris Buono from 40 Day Rhythm SWAT Camp
If you want to be rude, play everything on the upbeat. The basic building block of past and present ska is the accented andof each beat (Ex. 1). The tendency is to strum this apparently simple rhythm (often called the "clip") with upstrokes. But you get a fuller sound if you downstroke the upbeats because, with downstrokes, you hit the bigger strings first.
Modern skameisters often play clip rhythms on the treble strings (G, B, and E). However, the '60s Jamaican originators ska's "rude boys" favored fuller voicings as shown in Ex. 2, a I-VIm-IIm-V progression in G. In bar 3, notice how the Amchanges inversions.
For a truly rude flavor, add dominant-7th chords and sliding chromatic movement from either above or below the target harmony (Ex. 3). As illustrated here, occasionally it's effective to play on the downbeat.
Often called a "stuckey," a typical ska single-note riff features sixteenth-notes, played clean and very staccato (Ex. 4). Note the characteristic chromatic movement, as well as the arpeggiated chords.
These examples sound great with wah and work well at tempos from 150 to 190 bpm.