By applying the majority of white hat SEO techniques and outsourcing a decent part of my job to SEO software.
Honestly, when you manage more than a couple of sites and a personal blog you just have to have right solutions at hand and keep an eye on your rankings, competitors and things of the kind.
I personally love Rank Tracker (
http://www.link-assistant.com/rank-tracker/) and SEO SpyGlass (
http://www.link-assistant.com/seo-spyglass/) from SEO PowerSuite bundle.