The best advice I can give you is to learn to play every riff,intro and solo from any songs you like the sound of.Some would say you should take lessons and learn about notes,scales,keys,chords and such and they may be right,but lessons cost money.You can stay home,hunt,peck,pick,strum and play all night for free.Once you have learned to play several different songs you will be able to create something of your own by using variations and combinations of what you already know.Bottom line is this,the more you know the easier it is to learn or create something new.Also rember this,for every great song you hear,there are thousands that didn't make the cut.As my father always said,"writing a song is easy,writing a good song is not so easy".Keep rocking and best of luck.