One of my friends runs a few small SaaS businesses in parallel. He really likes a conference called MicroConf (http://www.microconf.com/) which focuses on bootstrapped businesses. That might be something to check out if you can make it.

One book that's great, regardless of what scale of company you're trying to build, is Traction by Weinberg and Mares. It talks about how to pick marketing channels for getting traction + includes an introductory section on each of two dozen popular marketing channels. Very useful if you're trying to get traction for your product and not sure where to start.

Finally, a lot of startup advice should apply to companies more broadly: focus on building something people want; it's better to have 100 customers that love you than to have 10k customers that like you; do things that don't scale at the beginning; etc.