The little red C on the keyboard indicates "middle C" to a keyboard player.? Do not tune your guitar higher than this diagram as you will break your strings

Tuning is not that easy for the uninitiated and it may take some practice to get it right if your ear is not accustomed to it.? It is necessary to train your ear by repetition and trial and error.? Eventually you will get a feel for it and tuning will become automatic.? To achieve exact tuning, if you are having trouble,? you can buy little electronic gadgets that help you tune your guitar perfectly by showing a little light to indicate if you need to tune up or down.? These are a great aid but you should still practice tuning by ear.