Startups vs. Small Businesses：
Shift per-unit costs into fixed costs (e.g. via software). Costly up-front software development can pay off in the long run.
Pricing is important; to the extent that you are not constrained by competition, you really do want to charge the highest possible price at the beginning to get into the black as soon as possible.
Measure growth rate per week, but only after you've launched. A good growth rate (during YC) is 5-7% a week. If you can hit 10% a week you're doing exceptionally well. If you can only manage 1%, it's a sign you haven't yet figured out what you're doing. Focus on just hitting a growth rate every week. This focus reduces the otherwise bewilderingly multifarious problem of starting a startup to a single problem. Use that target growth rate to make all your decisions for you. Having to hit a growth number every week forces founders to act. Nine times out of ten, sitting around strategizing is just a form of procrastination. Best thing to measure growth rate of is revenue for startups that charge initially, and active users for startups that do not.
Be aggressive when recruiting new users. Manually and individually recruit your initial users; go out to a coffee shop and have people try your product. Go door-to-door. Have people sign up for your beta in person. The numbers will seem small at first, but don't be fooled by compound growth - it starts slow.
One advantage of being small: you can provide a level of service no big company can.
Sometimes the right unscalable trick is to focus on a deliberately narrow market. It's always worth asking if there's a subset of the market in which you can get a critical mass of users quickly.
TL;DR recruit users manually and give them an overwhelmingly good experience, and founders need to work hard
You want to find a small market to quickly create a monopoly, and then expand. You've found it when people depend on it even when it's still a crappy incomplete product.