Know-How Exchange : Student Questions

Can anyone give me a basic overview on how to handle media relations for trade magazines? I am a marketing person w/15 years of experience, but my expertise is the web and marcomm. I am working at a startup, so now I need to handle everything. Our marketing is industrial software. I understand the basic idea is to get to know editors and pitch stories to them. But are there steps? Ex. what do I do with BusinessWire and PR Newswire? Should I put editors on our "mass" mailing list -- ie. should I send them press releases that I know they probably won't print, but just to keep them informed? Do I personalize each one -- ie. send press release with cover letter? I just really don't know the "standard steps." Thanks everyone!!!