After you’ve learned about what chords and scales to use if you want to sound bluesy (see these videos: 1, 2, 3), you can combine everything together into a simple tune consisting of a chord progression and a simple riff-based melody.
First things first, you’re going to want to learn the chords that you’re working with. The I chord is the most important one to learn first, and it’s going to be a Cm7 chord. That means it consists of the C minor triad plus a b7 note on top. If you want to spell out the notes individually, you’ll have C - Eb - G - Bb.
The next chord to learn is the IV chord, which in this case is going to be an F7 chord. This chord is built up of a major triad plus a b7 note on top. If you spell out each note, you have F - A - C - and Eb.
The final chord of this little tune is going to be a G7 chord. The G7 chord is built up of notes G - B - D - F. Naturally, this final chord in the blues chord progression is the V chord. As you play through each of these chords, take time to listen to how they sound together. Ask yourself what does it sound like to move from the I chord to the IV chord? What about the V chord resolving back to the I?
Now that you know the chords that will structure this song, it’s time to look at what the right hand is doing. The main riff for the song consists primarily of the notes within the pentatonic scale, with the blue note (aka the flat-5) added in for good measure. The nice thing about this riff is that it falls quite naturally under the hands in resting position. So keep your thumb on C and your pinky on G as your neutral position while you practice this riff!
Making It Your Own
Above all else, your blues playing should be a personal expression of yourself. Because these blues chords and riffs are so simple, try to personalize them a little bit by adding/exchanging a few notes here and there, or play around with the rhythms in the left hand. See the sheet music as the guideline, not the rule!