Growth Hacking -- getting your first 1000 customers

Being involved in early-stage startups, we always think about getting 100,000 customers, 1 million customers etc, when we pitch to investors. Because that's where the money is. However, what REALLY is difficult (and one of the many major reasons startups don't even get past the initial phase), is how to even get your first 100 and first 1000 customers. Customer / User traction builds upon EXISTING customers/users. Virality, no matter how inherent and how great, also builds upon existing relationships. But why doesn't anyone talk about the initial growth? The first 1000 customers cannot be obtained by virality nor networks. After the first 50-100 customers that are usually family/friends, where do we get the remaining 900 people to start building traction?

Finally, this very important but often forgotten topic was addressed at a recent meetup I attended, organized by a team of students from the Stanford Graduate School of Business, called "Igniters". The speaker was James Kennedy, founder of piehole.tv. They had recently obtained their first 1000 customers, so James was a perfect person to speak about the topic -- both success and fresh in mind. A few take home points that I personally felt were new and useful:

1. Brainstorm on 30 different ways to get leads, and 30 different ways to get conversion. Getting leads (the connection and the list of people) and conversion (leads becoming sales) is very different, so methods for both need to be brainstormed separately. 
2. Delete the 1st 20 things on both lists. WHY!??!?! Didn't you just brainstorm 30, why delete 20 of those now? The reason being -- the first 20 is probably extremely common, and everyone else is already doing it! Not to say that you shouldn't use any of them anymore (tried and tested), but if you want to be different, or if you aim to disrupt, go for the last 10 that you had to squeeze dry your brains to get to. 
3. Test only a couple of methods each month, using a metric to measure effectiveness of each method. Discard the ineffective ones after each month, and test new methods. Keep using the effective ones, and eventually dedicate most of your resources to the most effective.
4. A/B testing. Optimizely is a useful site to help you do your A/B test. (Hey, they have big-name customers such as Walt Disney Company, Fox media, Starbucks, techcrunch!) 

Let me know if any of these were useful in helping YOU get your first 1000 customers! :)