Raise start-up money. Create a detailed proposal for potential investors. This should include basic information on your product or service. It should also include ideas for expansion and development. Talk to as many people as you can about your business both in-person and using online networking tools. Attend trade shows and fairs, don't skip such though.
One of the cool things about Google AdSense is that it's so easy to get set up. If you have a blog or website, you can sign up for a free Google AdSense Account. From there, Google will give you a unique code that you will paste onto your website. Google takes it from there, tracking your page views, traffic, and earnings on your behalf. There is no upkeep or maintenance to get this thing going, which makes it a no-brainer if you have a website already.