hey everyone just wondering if people can give me some tips or ideas on how to write a metal song i keep making some catchy riffs but most of them can't be expanded upon then theres the whole lead and solo thing i can't write any solos. I don't where to start, somebody please help

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"We forgot to call Dylan" "Who the F*ck is Dylan?" "oh, I mean xDylanx" " oh yea we forgot to call him"

This may not apply to you and as of yet it is all I can write, but I'll share it with you. First I choose some diminished chords in a common key. You will ALWAYS be able to come with catchy riffs using them in any order. Then at the bridge I use the help of a modulation chart to help me go into something dark like A minor. In this new key I write the solo based on the appropriate scales for A minor, mostly pentatonic and aeolian licks. I might just be a Randy Rhoads enthusiast!