03 Start Simple The cheap and easy approach is to simply buy a track with an instrumental mix on it and write your own vocal to go over the top.
You can do this at home with a four-track recorder but, as you're trying to show off your voice, it'll be worth the extra cash for a couple of hours in the studio.
This will give you a better result and the engineer will be able to balance your voice and blend it into the track more effectively. They'll have better microphones so the recording will also be clearer.
Remember a track made like this can only be given away. It's copyright, so selling it may get you into trouble.