How do you get from your bedroom studio to the professional world of recording? There are several ways, but here's one…
There is a steady market among smaller dance-orientated labels for remixes. If you were already a pro, a label might ask you to remix one of their recordings. They would give you access to the master tapes and you could keep what you liked, replace what you liked and have 100% creative freedom.
For that work, you might get paid a fee of up to $5000. You are not likely to get royalties on a remix.
But if you are not yet a professional and you haven't made any contacts with record labels yet, what are you going to do? The answer is that you are going to have to work with the materials you can get hold of – commercially available recordings.
Since on a finished stereo mix, it is hard to find enough sample-able material to get creative with, you are going to have to use more than one source. Take a snatch of vocals from one track, a drum break from another, add your own bass line and embellishments, etc.
When you have created a killer remix, you can contact the labels (you can find out who they are from the records in your local specialist store) and ask them to listen. If they like your work, the rest might be (future) history.
Oh, but isn't it illegal to sample from records or CDs in this way? Well technically it is, so the official line is, “Don't do it!”. In practice however, blind eyes are turned until a product is released and starts making money. The label will sort out all of the legal stuff before release.