Ghost notes are great for the intermediate or the advanced player, and maybe a beginner. Ghost notes can be described as unaccented notes, or notes that are barely heard. Ghost notes quitely makes the drumming a little more musical. The quieter the ghost notes, the better it will sound. To do a ghost note, simply put your hands about 1-2 inches above the snare and do tap strokes very lightly. To do fast ghost notes, I recommend using your fingers to guide the stick.

For more information, click this link.

Also, watch this video also.

This video is also great too.