Setting Up A New/Used Guitar

Guitar Set-Up And Adjustments
1.Changing Strings ...The main thing to remember is this,if the bridge is not locked down,but floats(Strat style),only change one string at a time!And,if the bridge is solid,then you can take off all strings and then replace all the strings at once.And on a "Floyd Rose"type system,be sure and,block the bridge off before changing strings.That is,place something under the bridge that will prevent it from moving.If you do not do this,you will run into major problems when starting to tune up,even if you changed one string at a time!And on a Gibson Les Paul style guitar,no problems in changing strings.And don't forget the wrap of the string on the tuning peg is...bottom to top!
2.Tuning...Make it simple and go out and buy an electric guitar tuner!They are inexpensive and easy to use.
3.Truss Rod...This should be the first adjustment in a basic set up.And you can easily snap the truss rod if you do not know what you are doing!Most of the time it only takes a quarter to half a turn,at most a full turn.Look down the edge(outside) of the neck,looking from the peg head end of the guitar.If the neck is bowed upward,loosen the truss rod,if the the neck is dipped,then slightly tighten the rod.In general,the neck should have a very slight dip around the 5th to 7th frets,but never have an upward bow.And note...the weather or seasons will affect the truss rod.So,i generally have to tweak mine seasonally!***With a left hand finger,hold down the 6th string on the first fret.Now,with a right hand finger,hold down the 6th string at the 12th fret.now,you should see a tiny gap between the frets and the 6th string,around the 5th to 7th frets!
4.Action(string height)...This is really a personal preference.Obviously there should be no string buzzes.And,the lighter,the gauge string,the higher the action needs to be.And also,if you play with distortion most of the time,well,you can get by with lower action.You should not have to "press"hard to sound a note out.
5.Intonation...Play the harmonic at the 12th fret,now play the same note by fretting the note at the 12th fret. The two notes should match exactly if the intonation is correct.If the fretted note sounds sharp, then adjust the bridge saddle so that it moves back away from the fingerboard.If the fretted note sounds flat, then adjust the bridge saddle so that it moves towards the fretboard.***One problem I've seen a number of times is where a guitars intonation is set properly, but notes fretted between the 1st and 5th fret sound sharp regardless. This is almost always due to the fact that the nut slots are cut too high. The additional distance required to push the string to the fret is causing the note to be sharp.***Intonation setting is the last adjustment to be done in a set up,after truss rod adjustment and string height adjustment,and of course,do this with new strings.***Again,use a tuner to do this!And remember,if the note is registering sharp,move the saddle back,and if registering flat,move the saddle forward.
***The above steps should be done in the order listed***

*Moisterizing the Fretboard...To do this,i use Lemon Oil(without wax added),Formbys is a good brand.Only do this to a rosewood or porous wood fretboard.A maple wood fretboard,with finish,does not require this.