SEO is like a race, your site is competing against other sites to achieve (or keep) top rankings.   Some Webmasters seem to think that they are in a short sprint, so they try to use short cuts and constant tweaking to try to improve position.   In my view, these efforts only waste time (and money) while never gaining long term results. Since your site rankings usually move around anyway, trying to figure out if these “tweaks” did anything is next to impossible. 
I prefer to view SEO as a marathon and try to avoid the short term actions that tend to hurt your site more than help.   What are the long term actions that help your site and keep it well on the path to top rankings?
  •  Add good, valuable content on a regular basis.   For B2B, this can be case studies, applications, new product ideas industry incites etc.
     
  •  Make content as engaging, useful and entertaining as possible.   This could be adding videos, or putting applications such as calculation tools on your site, or putting a “library of information” that is useful to your target visitors. One example would be a garden center site that has a trouble shooting section for weed and pest control. 
     
  •  Engage in quality link building – find authoritative sites to link to yours.   Avoid the link building services that promise “high page rank links”. Most of them are garbage and can actually hurt your site.   Press releases, well written articles and industry specific directories will give you more link building mileage. Go for quality not quantity.
If you do the above things well and consistently, your site will soon find itself on the first page of Google.