Learn the chromatic scale (http://www.answerbag.com/q_view/861567), wash your hands before you play, practice slowly, use a tuning fork instead of an electronic tuner (they needn't batteries and they don't break), try to learn a few whole songs instead of just parts of a thousand songs, practice slowly, don't buy cheap-o guitars, don't fix or work on your guitar unless you are sure you know what you are doing, learn the basics of music theory, write your own tunes, and practice slowly. The correct way to replace strings: take off the old ones. Clean the guitar body. Clean the fretboard with a rag and some NevrDull (http://images.google.com/images?q=nevrdull&oe=utf-8&rls=org.mozilla:en-US:official&client=firefox-a&um=1&ie=UTF-8&sa=N&hl=en&tab=wi). Put new strings on, tune them up to standard. One by one, bend each string on each fret. Tune back up and repeat the process until they stay in tune. After four or so cycles they will be broken in. Ready to rock.

Find what you like to play and play it. Don't give up. Have fun.

Get an electronic tuner and tune up before you practice. It is important to always play in tune. Plan your weekly progress so that you wil have a goal to work toward and you will know at the end of the week if you achieved your goal. If you are playing classical guitar, concentrate on your right hand technique and on memorizing your notes. If you are playing any other style, learn a few new notes and about two new chords every week. After the first month of learning, try to learn at least one new song every week. Work on it until it sounds as perfect as you can do it. Every week, split your practice time into thirds; 1/3 of the time learning something new, 1/3 of the time reviewing what you learned in past weeks, and 1/3 of the time practicing technique (scales, arpeggios, exercises, strums, etc.). Try to practice at least a half-hour every day, preferrably an hour, and do this at least five days each week. If you can't practice that long all at once, practice at two or three separate times each day. If you want to improve greatly, try to sign up for lessons from the best teacher you can find. Evaluate the teachers you talk to like you were hiring them for a job because this is actually what you are doing - you are paying them a wage for a service! Good luck!