I've been playing for nearly a year now and I feel I have made good improvement in everything, except my riff creating ability isn't doing to well. Has anyone got any advice on creating good riffs?
Easy way to start, take a chord you like from one of your fav. bands songs. Then just mess with it and play other things with it.
Thats one of the big problems there, I can come up with good riffs in my head but the porblem is getting them out on guitar if you get what I mean
Learn some percussion.

A good riff (if I'm getting what you mean by a riff) is based around a rhythmic concept anyway, rather than a chord or melodic concept.

Some of the greatest riffs are, like when it comes to the melody/chords involved.

...but there's a great rhythmic syncopation happening, some interesting movement in the bass, and so on.
"Virtually no one who is taught Relativity continues to read the Bible."

Quote by bangoodcharlote
Just mess around a lot.

You could also try singing a riff in your head and then try to play it.

+ 38 1/16th

this is what i usually do, i'll pick up my guitar and just go at it often for hours on end and outta that whole time i might play something that makes me go "ooh that sounded f#ckin sweet, i gotta remember that"

also the guy who recommended percussion. that made me think of the intro to "train of consequences" which is badass in and of itself.
I guess I'm pretty good at writing songs/riffs. I work at a music store so I hear improvs all day and then I compile them all into a riff, then I'll base a song off of that riff. All you need is just one killer riff to make a great song.