Journalists
It is a good idea to have a list of journalists that you keep in touch with. Ideally, this information should be stored within your CRM and each contact should be marked (flagged) as 'Media' so that you can find them easily.
For each journalist, you need their first and last name; their job title; the media property (i.e. magazine) they write for; an email address; their Twitter handle; a landine and / or mobile telephone number; website address; and topics that they write about.
Having compiled a list of journalists, the next step is to email them and introduce yourself and your enterprise.
They key thing here is to think 'relevance'. Is your story relevant to this journalist? Why is this the case?
For example, you could email the editor of your local newspaper mentioning that you live and work in the area. Or you could communicate with a trade magazine when you have an interesting case study that they might be interested...