Many many many songs are written off the back of other songs. For instance, almost everything Oasis did
relied heavilly on copying The Beatles. A bit too closely for my liking. Unlike what the member of Oasis might think,
they created nothing new. And unless you are really willing to experiment and go way out there, everything will sound in some way
like something else. Like it or not we are all influenced by what we hear, even the stuff we don't particularly like :p
In any good book on songwriting you will be encouraged ( If being successful and popular in the POP world is what you are looking for ) to listen to
things like the top 40 regularly. Not only to get a good feel for what is hot at the moment, but is a song gets to no.1 then if you could immitate
that song without ripping it off you are surely on to a winner. Unforunately in the POP world, it is all about repeating the formular. The right chords
that have been used millions of times. Music X-ray will even mathematically evatluate your song to see if it has any of the ingredients that song that have
been a success in the past have. The more it sounds like something that has been a hit before... The more likely it is to be a hit.
Personally I hate this, but that's the way popular music is. It is basically nursary rhymes for adults as I like to call it. It is about making money, not music.
However. I would like to make some money so I'm trying hard at it too. I find it difficult though because I'm torn between trying to make something
that would sound Popular and the natural more inventive and creative stuff I like to write.
I guess what I'm trying to say is that the more it sounds like something esle the better, without it being a direct rip off. If it has been popular before,
there's no reason why it won't again because most people who are not musicians don't care. They want a nursary rhyme they can sing along to.
So don't worry if it sounds like a song that has already been a hit. Alter it a bit, melody wise or rythmn wise depending on how it sounds like another song.