other than the servo

glitching can come from many things ~

bad servo
bad receiver
motor (no capacitors, bad brushes causing arching, worn out or dirty motor)
a wire loom that is twisted up in knots
wires from ESC to motor crossing wires to another item like the receiver
ANY wire from anything crossing the antenna wire
antenna wire crossed over itself
arching from carbon fiber chassis (cured by putting doublelayer of servo tape under radio, esc, servo)

and motor wires should have at least one twist in them (can't remember the exact wording, buy something to do with eliminating some weird frequncy causing glitch)