Check the time signature, the two numbers at the beginning of the music. The top number refers to the number of beats in a measure (the sections of music between solid lines), while the bottom number refers to the note that gets the beat. For example, in 4/4 time, there are four beats in a measure and the quarter note gets the beat.
Determine whether the meter is simple, compound or asymmetrical. Simple meters will always have 2, 3 or 4 as the top number. Because the beats of compound meters are subdivided into three, the top number of a compound time signature will be a number larger than three but divisible by three. For example, a 6/8 time signature contains measures with six eighth notes. Because those notes go by too quickly to be counted as their own beats, we count the measure as two beats, each consisting of a dotted quarter note (the length of three eighth notes).
Write or count out loud the numbers of the beats to help better understand the rhythms. The beats of a simple (duple) meter are subdivided "e and a"; for example, a measure in 4/4 time with a quarter note followed by two eighth notes, four sixteenth notes and another quarter note would be counted as "one, two-and, three-e-and-a, four." The beats of a compound (triple) meter are subdivided "and a"; for example, a measure in 6/8 time with a dotted quarter note, three eighth notes and a quarter followed by an eighth would be counted "one, two-and-a, three-a."
Search the music for suggestions when you're trying to find the beats to asymmetrical meters. Since these meters have an odd number of beats, they can be counted in a variety of ways. For example, a measure in 5/8 time could be divided into a beat with three eighth notes followed by a beat with two eighth notes, or vice versa. A measure in 7/8 time could be divided into beats of two, three and four. Practice counting asymmetrical meters and writing out the rhythms, since it can be tricky to keep a consistent beat.