The problem with Odesk and Fiverr is that all of those freelancers offer you "mechanical" solutions which in essence translate either to number of link builds or content written in any of your blogs or websites. The trouble here is that Google is getting smarter and no longer falls for an extra number of links or just more written content (remember the last penguin update on Oct 19, it penalizes "thin" content websites).

What you need is a strategy and that strategy can only be conceived by knowing the following:

1. What keywords or terms are you trying to rank for.
2. Is there really a significant volume of searches being produced for the terms you want to rank
2. How well is your competition ranking for

The end result could be a combination of several efforts, a little bit more content on your website or probably placing or creating your content on other sites such as Youtube, Amazon, or other networks (That is actually what I did with my own site and was able to piggyback Youtube until we reached 1M uniques/month on our own site).

So here is what I do, research what keywords you want to rank for (volume of search and what other terms are people searching for. Market samurai is a great tool http://www.marketsamurai.com/c/hernan and actually just by watching their tutorials you will learn the intricacies of SEO. With this tool analyze your competition and watch what type of content they have and where they have it. You could easily conclude where the big opportunities are, maybe its on Youtube or listing your store on Amazon. The level of difficulty can be assesed in colors as seen on this demo:

http://www.noblesamurai.com/share/seo-competition/aizoaq7zjaos88008cww#historical