Why do you want SEO?  The best reason is to gain people coming to the site to purchase, read or other.  If you have nothing to sell and nothing to read, they will not be there long.  People making a website for family and friends to see what they are doing really don't need to worry about SEO at all.

White Hat SEO and Black Hat SEO:
White hat simply means doing it the right way and not crossing the rules with all the stuff that one should not do.  The reason to do "white hat SEO" is simply to keep future problems down to a minimum.
Black hat SEO is all the same entries, but creating a lot of links that are not really good and can later actually cost you rankings and scores.  That could cause google to actually drop you.  That is not good.  It does make the SEO Guru look real good for a short period of time.  Finally, if you want SEO done with Black Hat techniques, I am definitely not the person for you!

It is best to start with the basic design of the website where every page has a H1 header tag and 1 or more h2 tags.  The reason is that search engines look for those and the search the content below them. 
Example:  The header on this page is an H1 tag.  I will be sure there is at least one H2 tag and maybe more. 
The point is that a sight really needs to be built from the ground up with SEO in mind. 

Each page in a sight needs to have a Meta descriptionr and Keywords for that page.  These are a must!
Example: meta description is like a sentence describing the page.  This page has "SEO - Search Engine Optimization how to and how not to."  and the keywords has "SEO, black hat, white hat" inside it.

Sharing the pages are very important and your visitors need to be able to share the site on facebook, twitter and others they may have membership to.  Those little buttons are important.  Notice the wishbone at the top of this page? It willl open so you can share this blog.  That is important to me, the developer and people do it in appreciation for any help they get. 

Good SEO will include a page on Facebook, membership to twitter and any other you can submit to. 
Who does this part?  The person with the page, not the seo guru!

Good SEO takes a lot of work with everybody chipping in.

If you are going to do SEO for somone else, there are some questions you should ask first.
1.  Will you give me control of the site completely so I can correct the current errors or design the whole thing.  If No, get out
2.  How long have you had the domain name? and What site was it attached to before this?  If it has been out there for a while, you better check it's reputation first.
3.  Do you want Black Hat or White?   With black Hat, I am out, but you make your own decisions.
4.  Ask about verification sites like google analytics(there are others too) and whether they would connect to them.  It should not be your job to sign them up for that kind of stuff.  I prefer to get into the cpanel so I can see what is really going on and prefer to look up the site in This address (change aldaweb.com to whatever name you wish) .  This gives me a better idea what I need to do.
5.  Ask if there are a buch of domain names pointing at a site.  1 or 2 is ok, but 30-40 is definitely not.  If I am doing SEO on a site, those extras have to go. 
6.  If you are on at the beginning, try to choose a short domain name, but one that makes sense.  stuff like johnsbarbequeinalbequerquenm.com manot be that good of a choice due to people misspelling with all the letters. Use johnsbarbeque.com and specify the city and state in the keywords and in the text of the main page.  It might work better.
7.  Do you have keywords that you would like to use for searches.  I always get a list from the client and then go look at similar sites to see what kewords they may have used.  That is most helpful and remember, too many keywords can be worse than none.