The easiest and most accurate way to tune your guitar is by using an electronic tuner. This allows you to tune each string individually to the tuner, by indicating whether the notes are sharp (too high) or flat (too low). If you have an electric guitar you can plug it directly into the tuner. If you have an acoustic guitar the tuner will have an inbuilt microphone.
Tuning using other methods is difficult for beginning guitarists and takes many months to master, so we recommend you purchase an electronic tuner, particularly if you do not have a guitar teacher or a friend who can tune the instrument for you. If your guitar is way out of tune you can always take it to your local music store so they can tune it for you. Once a guitar has been tuned correctly it should only need minor adjustments before each practice session. To learn to tune the guitar using other methods see Progressive How to Tune the Guitar.