Go to local events or Meetup events and connect with bloggers in your industry. An example of an event I run to connect with bloggers and people in the online marketing word is: http://www.meetup.com/Online-Marketing-Sydney/. Make friends first and then try to gain guest posts later. I am not really a fan of websites which are flooded with guest posts one after another; it is the type of thing which Google is just waiting to target.
Stay on topic. All this socializing, forum commenting and question answering ought to be on your website's main topic. The more your activity and site content match in topic, the more likely the right people find it. The more targeted your affiliate links are to the topic, the better you'll do with them too. People don't mind advertising that's on topic, it starts to look like a convenience directory rather than irritating commercials.
For our client: We monitored everything on a daily basis. If something came up, which needed to be fixed, we were quick to implement it with the development team at the business. We also rolled out numerous campaigns multiple times as they worked effectively the first time around in generating significant traffic so it was second nature to do the same thing twice.