Working backwards from Sam's thesis, it seems the most logical first step would be to get your app in front of as many "real" people as possible. Show it to your friends, family, coworkers, your mailman, your mechanic, the dude sitting beside you at Starbucks. My 2 cents anyways...
Word of mouth is rarely authentic in the beginning. The key is to be able to plausibly manufacture it without being accused of spamming to any significant degree. AirbBnB, for example, got their start by spamming anyone that posted a listing for a rental property on Craigslist . Flappy Bird was very likely "growth hacked" with fake downloads and reviews until it went viral . Facebook's success essentially boils down to a contact importer that, especially in early incarnations, made it far to easy to accidentally spam hundreds of friends with invites to the service.
The reality is that while a good product is a prerequisite for something eventually having viral success, every tech success that I am aware of (except for Google perhaps), up to and including Facebook, has built their empire on spam and TOS violations. If you want to be successful, build something that plausibly fits into these kinds of tactics and spam away.
The backbone of all effective marketing is product. Period. Your first goal is to identify who, exactly, wants your product, and who wants it the most. You do this by getting the product in the hands of as many objective, unaffiliated users as you can -- ideally without spending too much money doing so.
Not everyone will dig it, and that's fine. If you find yourself in a situation where everyone tells you they love it, something is either ridiculously right (highly unlikely) or nobody is really, really telling you the truth.
You'll want to have a hypothesis in mind as to whom you're targeting -- start by identifying and sampling among these people. But don't be afraid to consult total randoms. The key is to seek objective feedback and observe actual usage.
Also, think of your hypothesis testing the way a scientist would. In some respects you are seeking disconfirming evidence, not confirming evidence. If you seek feedback with a conscious bias towards confirming your preconceived beliefs, you risk "leading the witness" and nudging people down the path you want them to. You also risk overcounting the positive feedback and emotionally discounting the negative feedback.
Once you believe you've found evidence of a core user group, stick to that group and overservice it. Be the absolute best solution for that group. Kill it with that group. Just be...absurdly, undeniably awesome for it. Then play around with referral hooks, mechanics, and incentives. This is how you sew the seeds of word of mouth.
A word on gauging positive user feedback: when someone really loves your product, you'll know. They will be begging you to let them know when and how they can get it. Genuinely positive feedback is usually very enthusiastic. Beware of "meh" feedback disguised as positive feedback. Remember: you are seeking awesome.
We've tried feeling the water with with /r/femalefashionadvice and the feedback was rather positive, that's what keeps us going still.
I have a feeling that feedback from total randoms might even be more beneficial, as feedback from your friends will probably be heavily biased, and, simply because they're your friends you share a lot of things in common, the sample will be much better.
Also, sometimes you just have to power through it and do it better than others. If we take Instagram as example, I have a feeling that a lot of their friends would have told them "why do that, there's already Hipstamatic that does the same thing" (at least that was my experience often), but they found their following online.