-maintain a good content and it should be easy for any users to read and understand i.e, make it as simple as possible.
-make use of keyword around 2 % to 4%.[follow keyword stemming but never stuffing]
-always try to create unique tags with in 70 characters.
-dont make use of duplicate contents.
-be carefull about broken links.
-optimize your code with meta tags,title tags,headings,site maps, URL strucures,domain name etc.,