To tune a violin, you will first need a tuner or a piano/keyboard. You will need one that makes the sounds for E,A,D, and G. You can use fine tuners or the peg method. Fine tuners are small screw looking devices found at the tail piece of the violin. Turn them wither clockwise or counter clockwise to match the correct pitch of the device you are using to tune. While not all guitars have have fine tuners the pegs can be found at the top of the guitar. As you turn the pegs, tighten or loosen the string as need to match the pitch of your tuner.