The very first post of my blog, over three years ago, answered this question. It's not difficult, and phrased correctly can even make people drop what they're doing and make it their life purpose to connect you.

Call and ask. This process has been described by a fellow trainer as, "Calling up a movie theater and asking for showtimes." Is that scary? Is that difficult?

Here's the post: http://www.salestactics.org/how-to-get-to-the-decision-maker/

I have many examples of me using it over the years; here's one (names erased, but this is a large medical device company): http://jasonkanigan.com/little-unsure-2014/

I use this technique all the time. And many, many other people I've taught it to have used it as well. Some were skeptical, but only those who had never actually done it. Then they'd come back and exclaim how well it worked.

Often you're sent through to a contact so fast you don't even know where you're being sent. When the person answers, or you get voicemail, you say pretty much the same thing to get confirmation ("I'm not sure we should be speaking, but reception transferred me to you; I'm looking for the person who handles...")

Don't wait for "all the information." With this method you don't need to know anything but the phone number to proceed. Get moving. Focused action will get you where you want to go, not looking around for the magic bullet.

If you're too chicken to make these calls, then odds are you shouldn't be running your own business. One way or another, you have to put in the work.