Again a great article from Rand Fishkin.

1. Repetitive Keyword Targeting
If you’re targeting a specific keyword term or phrase, it’s not necessary, and often ill-advised, to place that keyword in the title tag, H1 and body text of every page on your site. It’s certainly OK to use the term/phrase in passing and when relevant, but remember that pages target rankings, not sites – a good rule is to target one specific keyword term/phrase per page, sometimes more, but only in rare circumstances (like when you’re trying to get a secondary, indented listing) do you actually want to target the same term on multiple pages.

2. Splitting Efforts Across Many Domains
If you’ve found 10 reliable sources to get links, don’t fall into the trap of thinking you can register 500 domains, get them all links from your 10 sources, then link from those sites back to your main domain and suddenly appear to have a diverse domain backlink profile. Splitting up your efforts on multiple domains is, in my opinion, rarely advisable (see this post for more) and can seriously detract from your goal of gaining rankings on a single site. The days of link farms and link islands are long gone – with link acquisition, quality is slowly but surely getting the upper hand on quantity, so use strategies that will get you the right links, not just any link.

To read the full article, click here