Nothing really comes from scratch anymore, and music is no exception. The first thing bands talk about when they form are their influences, and they typically start off by (and never really stop) playing other people’s music. Entire genres, like folk, blues, and hip-hop, are based upon liberal borrowing out of either tradition or necessity. Simply put, every artist you love, no matter how unique, innovative, and game changing they may be, stands on the proverbial shoulders of giants.
I think the most important thing to be avoid of musical plagiarism is do not leave a paper trail leading right back to the song you supposedly plagiarized. In the case of Robin Thicke’s “Blurred Lines” vs. Marvin Gaye’s “Got to Give It Up,” Thicke had done multiple interviews name-checking Gaye as inspiration for his No. 1 hit. He told GQ, for example, “One of my favorite songs of all time was Marvin Gaye’s ‘Got to Give It Up.’ I was like, ‘Damn, we should make something like that, something with that groove.’ Then he started playing a little something and we literally wrote the song in about a half hour and recorded it. The whole thing was done in a couple hours.”
And one more thing, the real music comes from your heart not from other peoples work.