Learning to read eighth notes can be mastered by organizing rhythms into patterns across a 4/4 measure. With the exception of tied notes, this page covers nearly all rhythmic possibilities.
You can reference the meter (the quarter-note pulse) using a metronome or by tapping your foot. If your internal sense of time is strong, aim to feel the pulse internally as you play. Counting the beats out loud can also help align your playing with the rhythm.
As an added skill, work on coordinating your picking with the meter: use downstrokes on downbeats and upstrokes on upbeats. This reinforces rhythmic accuracy and develops a strong connection between your picking and the eighth division.
