How do you put riffs together?
Instead of trying to weakly incorporate it into the song, write it down, and save it for later. From there, try applying your riff to a certain section of the song then play around with it. The best way to get a feel for these songs is to just listen to other songs and get a feel for what professional artists do.
What is an example of a riff in a song?
A few examples of riff-driven songs are "Whole Lotta Love" and "Black Dog" by Led Zeppelin, "Day Tripper" by The Beatles, "Brown Sugar" and "(I Can't Get No) Satisfaction" by The Rolling Stones, "Smoke on the Water" by Deep Purple, "Back in Black" by AC/DC, "Smells Like Teen Spirit" by Nirvana, "Johnny B Goode" by ...