While it may be counterintuitive for me to tell anyone not to hire a (or to potentially fire their) publicist, there are some that either can't afford to or don't want to retain an agency or consultant. For those, there's oftentimes the self-serving advice of an agency or "PR guru" that says that they simply can't do it alone. The truth is that hiring a great PR person or team is investing in their connections, their ability to tell your story intelligently and their time. You can do what they do, if you've got the time and the know-how, and I'm happy to share some of the ways.
1. Follow the media like a stock. Treat them like a friend.
According to friends and family I live most of my life on Twitter. Though it's not the main reason I'm on the social network, it's become the easiest way to follow the comings and goings of many media outlets and reporters. There are many that actively post their own stories as well as discuss things of interest to them--even if it's another reporter's article. Understanding each reporter's job and flow of stories on a business level yet approaching and dealing with them on a genuine level will make your eventual pitch that much more effective.
2. Build relationships before you pitch.
Once you know who the right reporters are, try and interact with them both on social media and in person. If it's a networking event for reporters and startups, approach them and don't talk about work for a minute. Build a relationship based on your value as an actual person (IE: you're interesting, you're interested in what they have to say, etc.) and wait for yourself to be asked about what you work on. This also includes if you ask a reporter to grab coffee. Even if it's simply establishing that you're an intelligent and thoughtful human being, this improves the likelihood that you'll actually get them to listen to your ideas (or care about them) in the future.
3. Use the right software for the job (and don't form pitch).
The classical PR formula is to buy a contact list or access to a database and send the same email to each reporter in the hopes they'll use the materials inside. This seems time and cost effective, but actually leads to fewer results. Instead, focus on creating a structured "skeleton" of a written pitch, perhaps a one-liner that works, and customizing the rest to the journalist. This is easily done by sending emails using Toutapp or Yesware, creating a simple structure to build a pitch in that you can drop into an email automatically, and customizing from there. Looking to appropriately understand a reporter or an outlet's body of work? Muckrack is rather expensive but comprehensively shows a multitude of reporter's actual stories, along with their social presence. You can also use it to search for articles (or run regular searches automatically) on any term you want. This is the core of research that will make getting your own publicity.
4. Send fewer, better emails.
While you may be tempted to set a sales-style goal of 20-30 emails a day, sending 5 to 10 well-targeted, goal-oriented pitches will net more results. For example, if you're an expert (a true expert--such as a PHD in a particular field or a specific kind of lawyer) and present yourself to the right reporter, with the right pitch, at the right time (because you followed and read up on them) you'll see better results than 100 generic, unplanned pitches.
5. Stay (appropriately) humble when you pitch.
If you're talking to a reporter, be it over a short (120-150 word) email asking them to take a look at your product or over coffee, calm down. Don't breathlessly tell them that your device is going to change the world. Even if your company is doing something truly world-altering, you should keep your tone as fact-based as possible. When I pitched and secured an interview for Rob Rhinehart, CEO of Soylent, with The Economist, Rhinehart's language was honest, blunt and straightforward. While he called his own food a potential solution to world hunger, he justified it with facts. You should never assume that what you have automatically changes the world; you should say in simple language why it matters to the person you're talking to. That being said, don't hide the positive parts of the product; just don't hype them.