Guitar Tuna - This is an excellent tuning app for Guitar, Ukulele and Bass with games to test your knowledge of chords too. See if you can beat my scores when you download this fantastic app from your App Store. 

You definitely can't practise with an out-of-tune guitar anyway, so please try out this tuner WITH HELP FROM AN ADULT. Remember that strings will break if you are not careful and your strings should only need a little half turn at most. Look at the diagram above so you know which notes you are expecting your guitar to play. EBGDAE