The only search engine that matters really at the moment is Google. If everything is done right, then all pieces of the puzzle will fall into place. However there is a big wrong assumption by most people that search engine optimization is something easy. Most would say that is just a matter of meta tags and links. That is completely wrong because that would mean Google is easy to trick, which is not. In fact is impossible.
The Google algorithms cannot be tricked easy as it was in the early 2000 and even if you would be successful that would be for only a short while, using black-hat seo. The brains behind the searches at Google have made searches better, so that more and more relevant searches appear at the top of the search lists and not so much those with thousands of links. These days to get at the top of Google you need quality content which will directly result in more engaged readers. Engaged readers are easier to transform into regular customers. When someone is more interested in the relevancy of your content they will also be more inclined to chose your products or services.
One of the problems in producing quality content is that it is very time consuming and it requires writing abilities. Also you need to allow your website to be interactive and communicate with your customers. Give them easy access to posts in your forums, allow them to find your contact details quick and then you would probably start to get some income. Once some of the main keys are touched, your website starts working towards your benefit.