My wife and I are bootstrapping a business, and we're nearly at 100 customers (92 right now). I would not say it's an easy road. We've been working on it full time for 1.5 years so far.

A couple things I've realized while doing this:

1. Business is a competition. Much like in sports, skills are only built up through practice. For an entrepreneur this means actually selling something. You will start at level 0. There is no substitution for actually doing the work.

2. The bigger you grow, the easier it gets. A year ago we were running around like headless chickens not knowing what to focus on. Now that we've got a core group of customers, and it's much easier to decide where to go. We can start to plan a month or two months out now. Opportunities such as partnerships also present themselves as your business grows larger.