Textures are your friends.
• 6 Brown Paper textures on Lost and Taken - Link (above)
• Wood/Bark on Keep Designing - Link
• Vibrant colorful grunge on WebTreatsect - Link
• 10 HQ jean on Naldz - Link (also above)
• Random grab bag = Awesome on Bittbox - Link
• Blue metal w/rust on PsdzTuts - Link