Setting the truss rod to ensure a properly straight neck, setting the action, cleaning, setting the intonation, setting up the tremolo system if the guitar has

Setting the truss rod to ensure a properly straight neck, setting the action, cleaning, setting the intonation, setting up the tremolo system if the guitar has one You grab a guitar off the shelf and you can find it has buzzes, or the action is a bit high, or it sounds right open and with chords near the nut but sounds off as you move up the neck.