Most grace notes can be defined as very short approach notes.
An approach note is a note that leads to the main note.
It helps you approach that note musically.
Approach notes can eitehr approach a note from above or below, ty pically the nearest scale step.
Unlike grace notes, true approach notes are played in time, and notated appropriately using quarter, 8th or 16th notes.
In addition to the traditional single approach note, you can also play multiple approach note runs.
The approach note run must be strictly linear, using step-wise motion.
For eg. a lead up to a note with four 16th note approach notes, you start 4 steps below the main note and run up one scale step at a time.
Approach note runs are part useful in building up to a big note in the melody.
Notes of the run anticipate and ina way announce the main note.
Tip: approach notes don’t have to be part of the underlying scale.
If you are playing a jazz tune or a pop tine with particularly sophisticated chord progression), you can use chromatic approach notes that move in pure half steps toward the main note.