Yeah for me a combination of quality, informative, audience driven content comes at the top of my list. In second place comes a certain degree of publishing your work like posting in the right groups and inviting people to like your page. That said I still have my doubts that FB likes are all that helpful for promoting your business or website.Providing creative contents is one of the factors for increasing the number of your like. It is really important to do so if you want to have more likes. Try to keep content useful and short as people won't be bored. You can also ask your friends to help you if they have a fan page with much likes. There are also websites which sell like but you should pay much money if you want many likes.