As far as search engine optimization is concerned, everything essentially boils down to 3 things you need to know before hiring an SEO company. Step 1 is finding out what services to ask for (or not), and step 2 is to gain an understanding of the differences between good and bad consultants. Step 3 is figuring out the time period for the campaign, which is very important in terms of the hiring model, budget and expected results.
Every service or component in the campaign can be classified as either offsite or onsite work. On the site, the essential components include traffic analysis and keyword research to create a list of high value keywords associated with the website. This will be followed by content optimization, which means modifying pages and creating new ones focused on the keyword list.
Functionality and design changes are needed, with style sheet and scripting additions or deletions to make the website easier to use and more useful. Page loading speed can be improved by upgrading to a better hosting package. Some consultants may even recommend moving to a host who offers Class-C IP addresses and other such SEO-friendly elements.
It was necessary to explain this because many times SEO consultants lose sight of the big picture in the process of trying to push rankings up for specific keywords. This means practices like cloaking, redirections and stuffing pages with hidden text. Search engines will see a keyword heavy page while actual visitors will be seeing something entirely different.
Avoid such services, and go by a rule of thumb that any onsite service that makes the website better for visitors is acceptable. As for offsite work, the list of available services will be confusingly large. Forget everything else for now, because all it really needs at first is a link building campaign, a presence on all the major social networks, and a blog.
In this case too, some providers may try to apply short-cuts to get fast results. This means using link farms and big chains of sites and blogs whose sole purpose is to provide links. The golden rule here is to make sure all link acquisition techniques will focus on getting links from sites that actually send visitors. Also try to focus on sites that happen to be in the same sector, including competitors.
The question that needs to be asked now is about the time-frame. The goal, in this case, is to get pages on the site to rank in the top 10 for a list of high-value keywords with heavy query volumes. For large websites with hundreds of pages and competition from other established and popular sites, an entire team will be working hard for a year or more to create content and acquire links to get anywhere near the top 10 for all the keywords.
If the site is small (5-10 pages) and the competition is not so tough, the job can be done in 3-6 months without a big team. The point, again, is to stay away from providers who claim to help clients reach the top 10 in a month. This is a laborious process that needs talent and hard work. Unethical practices will only result in the site getting banned and pages removed from the search index. Assuming the 3 things you need to know before hiring an SEO company are now clear enough, it is time to look around and find a provider willing to work along these lines.