Attempting to replace a dead link with your own is easily and routinely identified as spam by the Wikipedia community, which expects dead links to be replaced to equivalent links at archive.org. Persistent attempts will quickly get your account blocked, and your webiste can be blacklisted (the Wikipedia blacklist is public, and there is evidence that Google uses it to determine rankings), which will have negative SEO consequences.
Achievable: Make sure you're grounding your goal in reality. Sure, you can't control a massive Google update, but using the history of your sales and competitive data, you can make some inferences. You also need to make sure you have agreed-upon goals. Get buy-in before you set the goal in stone, leveraging the thoughts from the leaders, merchandisers, analysts, and anyone who might be able to provide insight into the likelihood of hitting your goal.

If you havent see it already, check out the links in shor's comment below - there are some great resources in there. In some cases you can also consider surveying your current audience or customers through email, on-site surveys or SurveyMonkey.  Be sure to ask for some profiling information that you can use for determining specific persona needs like age, sex, location, etc. (Probably best not to make it sound like a creepy text chat like I just did though...)  :)
If you do great work with your search engine optimization (SEO), it could mean a significant amount of revenue for your business. At the same time, however, it is also an ongoing initiative. Once you generate a steady stream of traffic from SEO, you need to constantly be maintaining and improving your SEO in order to keep those rankings you worked so hard for.
Social media websites are among the most valuable resources a business can have. Sites such as Facebook, Twitter, and LinkedIn are chock full of members of your niche audience and other potential customers waiting to be found — so be sure to share your content with them! It can even help answer many of their questions while simultaneously establishing your credibility.
Simply put, search engine optimization (SEO) is the process of optimizing the content, technical set-up, and reach of your website so that your pages appear at the top of a search engine result for a specific set of keyword terms. Ultimately, the goal is to attract visitors to your website when they search for products, services, or information related to your business.
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