Outlets won't typically come to you unless you have an existing relationship with an editor, or maybe it's a publication under the same umbrella as another one you're writing for. It's happened here and there for me, but it's rare, and they haven't typically been big, worthwhile opportunities (unless I'm completely blanking on something).

As far as branching out, I can definitely speak to both of those examples that you mentioned. It's arguably better to come with a great feature pitch, because that shows your skill for generating interesting ideas and hopefully shows that you know the outlet, understand its readership, and have an eye for what kinds of coverage they'd be interested in. Plus, a lot of feature ideas won't require special hardware or any kind of above-and-beyond access, which makes them idea for both newcomers and remote freelancers.

That said, I certainly have found work sending a cold pitch e-mail to an editor and essentially stating my credentials/experience and asking if I can get involved. It's not always a worthwhile route, and I imagine some editors won't even bother reading what you have to say unless you're coming with a pitch; but once you have some great clips under your belt, it's certainly easier to just say, "Hey, this is what I've done -- I'd love to do the same for you." One thing I'd definitely recommend is to try and build relationships with editors on Twitter before you ask for work. Follow them, reply (meaningfully and non-annoyingly) to things they're discussing, and just try and get yourself on their radar. Be smart and subtle about it, though.

And certainly keep an eye out on Twitter or editors' blogs or wherever else you can think of for help wanted notes, or even hints that they might have a need for freelancers or feature pitches or whatnot. There are so many different ways to land freelance gigs in this industry, and you need to be assertive and (lightly) aggressive if you're going to land a few.