Anchor text without proper keywords
There is no use if you get a quality backlink and links it with a useless anchor test such as "click here". You need to build keyword rich backlinks if you want to see good results. Whenever you are getting a backlinks from a site such as PR4 or above, try to use your keyword or related keyword as anchor text.
Update: But if I find a high PR or high quality site to get a backlink from, most of the time I try to use my main or related anchor text... nd on others I use it to vary my anchor text.
After Penguin, I keep my main anchor text below 30%. Then use other related keywords for 50% of the links.. other 20% are un-anchored and other misc keywords.
Low - Quality Backlinks
Never get backlinks from a site that loos spammy or have a bad reputation. Look it this way, if you're hanging out in a bad neighbourhood, search engines begin to see you in the same light. So make sure you are getting backlinks fron good quality sites only.
Quantity over Quality
One quality backlink is always better than 100 low quality backlinks. Quantity matters but what you need to know that backlinking isn't just a numbers game. Don't waste your efforts getting thousands of low quality backlinks. Instead focus on getting backlinks from high quality relevant trusted sites.
Ignoring low PR sites
Many guys just focus on getting backlinks just from high PR sites. This could have a negative effect on your PR. The thing is PR is not everything, if a site has a low PR is necessarily doesn't mean that it's of low quality. A good site having a PR0 could have a PR5 in next few months.
Not linking out
If someone says that linking out results in losing your link juice, that BS, don't believe it. Linking out can attract linksi n return ad also help your to build a good network with fellow bloggers. If you want to recieve you need to give out first.
Hope this helps a few fellas here. Please let us know if you have something to add that would be helpful to all of us.