Start from the user: resident homeowner.
* Are you looking for people who are in a specific context, doing a specific action? For instance if they install a new alarm system, are they are more likely to use your app
* What do they read in general?
* Where do they go for articles when they are in their 'my home' context?
* What do they look at or read after they installed the alarm system?

The answers to these and further questions will help you identify the right segment.

There are some algorithms which usually work

1) Define circle of your competitors and similar companies.
2) Find person who wrote about them in past 6-12 months. Use Google Search or tools like Mention. Also you can use twitter search. Because good media professionals always twit about everything they do.
3) Use BuzzSumo to define more trustable and relevant among them.
4) Don't try to cover dozens of persons. It's useless and ineffective.
3-4 local, 3-4 nationwide, 3-4 global is enough.
Accuracy is thing which defines success in this field, not amount!

Otherwise, you become bothersome spammer.

5) Remember - you "tell the story". So the main rule here - think on media specialists and journalists like your agents, delivery mans. Don't make them think. Just give them real story which works.

That's why you should focus on really authentic and honest message. If story "catches" journalist's mind and heart, so he/she can deliver it to audience and catch them too.

6) Also try to combine your efforts with ProductHunt. It's an great opportunity to spread your product idea.

And one more advice...

Don't forget about your product and business. Very often startups spend too much time to DRIVE an ATTENTION to future product, instead BUILDING something that is WORTH this attention

Hope, it will help.

Have a nice day.

Start by signing up for HARO and see what kind of media are already looking for contributions for topics relating to your venture. Then follow-up with an offer to contribute to a targeted article about your venture. When you begin by offering value up front as a contributor to their article, you start building relationships that can yield you results later-on.

The next easy step is to identify where your customers are already likely to be looking. Find out what type of news your target market reads. It's probably best to be more refined than just "home improvement." Maybe you decide it's stay-at-home parents who are couponers and also like home improvement. It's much easier to define the right outlets when you've limited the scope of your audience.