Another useful musical technique is the trill. A trill is a rapid alternation between two notes as demonstrated in the following example. A trill is indicated by the symbol J above the two notes concerned. The first note is often written as a ghost note. Listen to the CD to hear the effect of the trill.
Here is a musical line which makes use of the trill. Experiment with trills on different notes. You will find that some combinations are much easier than others, but it is worth developing the difficult ones as well.