Publicity hounds need to know their media, so make an effort to read the magazines and newspapers or watch the broadcasts you're pitching to learn what kinds of stories they cover. Tailor your pitches to match their needs. For example, if a magazine or newspaper writes a regular column about financing a business, pitch them on how you raised the money to launch your company. Or for broadcast TV and radio shows that focus on health and fitness, send in a pitch about how your company's employees jog at lunchtime. By gearing your pitches to each publication, you up your chances of getting coverage.
In addition, do this type of research for more than a week or two. Read several back issues, or watch a program for several months. Spend adequate time to get a true feel for what the medium is looking for. It also doesn't hurt to be a subscriber if you someday intent to appeal to the editor of a targeted magazine.