Definately put your efforts into your own work. I started subbing when I started the business. You end up getting brainwashed into thinking that their work is the be all and end all, so in the end you have no time to build up your own business. Nothing wrong with subbing if you get the mix right, after all, one lump some cheque each month does help out.
but good luck with it, I know its a tricky one.