Tuning Your Guitar:
Learning to tune your guitar is a process that takes time, and kind of grows into a maturity over the first few years of playing. You have to develop an "ear" ... you must become familiar with the nuances of what's "sharp" and what's "flat" and what's "in" pitch. I think a good practice excersize is to play with one note ... tuning it to pitch ... raising the pitch and *hearing* what "sharp" means ... lowering the pitch, and *hearing* what "flat" means, and so on.
Learn to know when the pitch is sharp or flat ... take some time to twist a tuning peg around and listen to a note move to the flat or sharp zone so you become familiar with which is which. Do this by fretting the D (4th) string at the 5th fret and playing a G note, while you twist the G (3rd) string above proper pitch ... then down to match the exact pitch ... then below it ... and back up again. Do this a million times.
Also, here are some cool books about tuning your guitar:
@ Tuning Your Guitar
by Matt Scharfglass, Donald Brosnac
@ Tuning the Guitar by Ear
by Gerald Klickstein
@ Guitar Tuning Pack :
Everything You Need to Know About Tuning the Guitar
by Dale Turner
NOTE: Electronic tuners are great tools ... especially on stage, when it can be hard to listen to the pitch variances involved in tuning. But aside from the stage, you should learn to tune your guitar by ear. The more familiar you become with tuning by ear, the better you will be at discerning the accuracy of what you're doing, even when you are using a tuner. Don't develop a lazy ear by using the tuner all the time!
------- Alan Horvath