There are basic rules to follow for SEO, and then there are labor intensive site promotion activities that you can do on a daily basis that add tiny increments that over time eventually add up to a boost.The ROI curve for these time-intensive activities is, in my experience, not linear.  There's a point at which you could easily devote 8 hours a day to pumping your sites and yet see very little return for it. How much time do you spend, and what routine do you follow for SEO? 
How much time do you spend for SEO?
seo;site maintenance