Watch the Tweak the Sections online guitar lesson by Ravi from 1-2-3 Songwriting
It's tweak time! Play your song down from top to bottom and see what works and what doesn’t. Make it as perfect as you can because you never need to live with something that bothers you. The trickiest part of a riff is that it battles with the melody, so don't be afraid to modify it a bit whenever the vocals need a little more breathing room.