OK I admit the following aren't directly targeted to "ranking better in Google" - who the hell knows how to do that these days.... :) - but they should in THEORY help you rank better (according to Google guidelines), and none of the below will harm your rankings.
#1 Diversify your online income as much as you can (without compromising the quality of each site/venture).
#2 Related to #1, if you have any spare time in your general workday, think of a new site or new online venture to fill that work time up with, or something productive to add to your current sites. In other words, get even more disciplined. Work hard. It's as much about working hard as working smart these days (sadly!). Some may disagree, but a good work ethic never did anyone any harm, and it might bring you a bit of luck too.
#3 Related to #2, spend less time on places like webmasterworld.com and other SEO forums. How much do you REALLY learn from these places? Whatever it is you DO learn, you can still learn it in one or two visits a week rather than 10 visits a day (I'm berating myself here, believe me). Finish reading this post and leave! I promise to finish writing this post and leave.
#4 DON'T check the SERPs to see where you rank or what's going on there. It's a BAD HABIT (a habit I quit and then go back through sheer intrigue, but it is a bad habit). Why do you need to check the SERPs? You will know how well you're doing via your site visitor stats. Forget about the SERPs no matter what. I think it's unavoidable during exceptional times like a Penguin update, but for all other times of the year (95-98% of the year), forget it.
#5 Forget about the idea of building links, and think instead about building organic traffic through referals. That normally means guest blogging. The better your writing, the easier it is to get published. Insist on nofollow links to be on the safe side. I know some will disagree with that, but it's easier to be collateral damage if one of those sites you get published on is caught selling links / advertorials and your link is deemed as "bought". How can you possibly vet every site you publish on 100%? You can't. And who cares - if you're getting decent referal traffic, who cares...
#7 Pick up the phone and network. I've found the phone next to my laptop is a great social networking device. I've networked with fellow web developers and we've swapped work and guest articles. Network with fellow professionals. They're very receptive as you're talking about related matters. On the scale of hot to freezing, these are warm calls. Offer them something and ask for something. This is old-school business and has solid laws and principles that don't really change because they're based on human nature.