This is the single most important thing to your online business and as the head of that business you need to know exactly what makes it tick. If you leave it up to snake oil salesmen you'll be in for a wild out of control ride and have absolutely no control over your own business's destiny. Doesn't mean you have to do all the work, but you better know exactly what these people are doing to your business and the ultimate impact of their actions.
In my opinion most SEO is not a quick fix you can hire someone to correct. SEO is a way of doing business on the web and should be designed into every aspect of the web site from the ground up, not done as an after thought.
Assuming you have an ecommerce site even the software you choose and use could make or break you regardless of who does your SEO.
- Does category and product titles show up in the page titles per page?
- Do product descriptions show up in ALT text on your product images?
- Do your categories and products have a dynamic page name or is the category or product used as the page name? For instance do you get to the product via a link like [example.com...] or something more search engine friendly like [example.com...]
If the answer to all of the above is YES you have a huge head start.
These sound very simplistic but are shockingly missing in many modern sites.
Every category and product description in your site is part of the SEO process and you really don't need a 3rd party to fix some of these things. Many of my customers initially just used the brand, product name and/or part number only without any generic description at all in a prominent spot which resulted in lackluster results. The problem with that approach is unless I'm doing a search specifically looking for that specific brand and product, assuming I know the exact thing I'm looking for, I'd never find their listing. To correct it all they had to do was add the proper generic keywords into the category and product descriptions and the sales took off.
For example, if you're selling WIDGETS and you have Brand X's "Toldeo", many people merchandise it with the category being the brand and the product being "Toledo" so the term "WIDGET" never gets into a prominent spot for the search engine to find. Simply changing the category to "Brand X WIDGETS" and making each product contain the name term like "Toledo - WIDGET" and weeding WIDGET into the detailed description shot them to the top of WIDGETS. This is a no-brainer as suddenly the search engine understood what in the heck they were trying to sell - WIDGETS!
For LINK building, if you're running an ecommerce site the easiest way to get inbound links is start an affiliate program that directly points to your domain. Don't use programs like Commission Junction or Linkshare that redirect thru generic link counting domains. Try MyAffiliateProgram by Kowabunga as they do direct linking meaning you generate sales and increase your inbound links all in one shot. If you're lucky you'll get some authority publisher sites in your industry to become affiliates which helps improve your position signigicantly AND you make sales in the process, a win/win for all.
Hope this helps a bit.