The easiest song to play is the beginning of Ode to Joy. It won’t take you long to perfect, and will get you started.

One of my favorite, and not too terribly hard, songs to play on guitar is Moonlight Sonata – it forces you to learn finger picking and chord manipulation in order to play it…a must for classical guitar.

A couple words of advice for classical guitar
*Learn finger picking early on and don’t use a pick

*Allow your fingernails on the picking hand to grow to a half centimetre or so, OR get finger picks to get the best sound.

*Don’t cheat on any of the pieces. If you are having difficulties, slow it down and play it right until you can play it at normal speed, don’t fake it.
References :
I’ve played guitar a while