Most applicants don't have publications, but if you have one, it is sometimes helpful. Fewer still get to be first or second author. Your best bet is to get a lab job in a hospital or academic setting that cranks out a lot of papers per year, and find a PI who is generous at giving out publication credit to his people. Push for more substantial role in the research project as you become good at what you are doing. And with respect to your question as to "fastest", don't expect to get published in a very short time period -- research doesn't always work like that.