Re: Writing Metal
I'm not a big metal head, but this approach often works for me when I'm stuck writing a song.
1. Take three songs that you know and like . . . they need to all have a similar vibe, and should be from the same genre.
2. Break down all of the guitar parts in those three songs that you like and figure out what the guitarist is doing. (What scales/modes are being used, what kind of rhythmic patterns are being used, what tuning is being used, are the open strings being hit, how do the drums and bass fit together with the riffs to drive the song forward, etc.)
3. Come up with a simple rhythmic chord progression (or drum/bass line) that you like. Now approach the riff writing using the techniques that you've discovered in #2.
Bam. You get a new riff for a song in a style that you like, written by you.